Description:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)

“A MONOPOLE PATCH ANTENNA FOR AIRBORNE DATA LINK RADIO COMMUNICATION”

BHARAT ELECTRONICS LIMITED
with address:
OUTER RING ROAD, NAGAVARA, BANGALORE 560045, KARNATAKA, INDIA

The following specification particularly describes the invention and the manner in which it is to be performed.

TECHNICAL FIELD OF THE INVENTION

[0001] The present disclosure/invention relates generally to antennas and more particularly, to a monopole patch antenna for airborne data link radio communication.
BACKGROUND OF THE INVENTION

[0002] Generally, antennas are well known in the art which is a metallic structure used for transmitting and receiving electromagnetic radiation/waves for communication applications, identification applications, and the like. The antennas are of different types based on the requirements.
[0003] Nowadays, due to the vast development and growth in the field of aircraft communication, an aircraft is in need of establishing a number of links for its transmission. Thus, all air-borne antennas were required to transmit and receive a number of different signals in modern wireless communication and in ultra-wideband (UWB). The systems require antennas characterized by simple geometry, small size, and quasi-uniform radiation characteristics for the frequency band of operation. The types of antennas like dipole, slot dipole, helical antenna also provide Omni-directional radiation pattern, but due to their large size and limited bandwidth their uses are limited to few applications only.
[0004] Monopole antenna is a type of radio antenna consisting of a straight rod-shaped conductor, often mounted perpendicularly over some type of conductive surface, called a ground plane. This type of antenna is commonly used in wireless communications applications. Some of the important characteristics of a monopole antenna may include its low profile, wide bandwidth, and low radiation resistance.
[0005] Some prior art on printed monopole antenna for broadband, narrow band and multiband is provided below. Monopole antenna is highly sensitive with respect to surrounding objects, so its application is very less for critical missions. Lot of work has been done on this previously some of them are listed below.
[0006] One of the prior art discloses a dual band monopole antenna. This prior art provides printed monopole antenna for dual band. The antenna of this prior art has printed structure on both sides of the PCB material. This prior art antenna caters operating band around 2.4 GHz (2400-2484 MHz) and 5.2 GHz (5150-5350 MHz) for WLAN operations.
[0007] Another prior art discloses a printed monopole antenna, having a spiral copper foil formed on a substrate. This prior art antenna can be placed vertically on other integrated PCB. This prior art antenna is designed for ISM frequency band of 2.4 GHz and having a bandwidth of 110 MHz around the center frequency.
[0008] Another prior art discloses a broadband omnidirectional metal-plate monopole antenna. This prior art discloses a step-shaped metal-plate monopole, which is easily fabricated from bending a metal plate and is mounted on a ground plane is excited through a feeding post connected to center of monopole lower edge. This prior art antenna is designed for frequency band of 2180–6590 MHz and gain is greater than 0 dBi across operating frequency. The dimensions of the antenna are 100*100*24 mm3 (1.46λg*1.46λg*0.35λg).
[0009] Further prior art discloses design and analysis of monopole antenna for single and multiband applications. This prior art describes a printed monopole antenna which has fractal geometry for obtaining multiband on FR-4 substrate which is fed through a coaxial probe fed. This prior art antenna is having bandwidth of 350 MHz in the frequency range of 2.4GHz and having a bandwidth of 1.2 GHz from 5.8 – 7 GHz and dimensions of antenna are 25*24*1.6 mm3 (0.53λg*0.512λg*0.034λg).
[0010] Further prior art discloses a broad band circularly polarized monopole antenna with modified ground. This prior art describes a deformed monopole fed by a coaxial probe placed on the upper layer of the FR-4 substrate. I-shaped-slit-embedded square ground with an L-shaped branch is located on the lower layer of the substrate for generating circular polarization. This prior art antenna is having impedance bandwidth of 1.82 to 4.21 GHz (79.3% centered at 3.02 GHz), gain is greater than 2.0 dBic across frequency of operation and dimensions of antenna are 45*53*0.8 mm3 (0.45λg*0.53λg*0.008λg).
[0011] Several studies have been done on planar micro strip based monopole patch antenna but most of them focused on either improving bandwidth of operation or improvement in H plane radiation pattern. Those designs are suitable for normal operating condition but for airborne applications such antennas will not be able to handle applied vibration, shock, thermal stress.
[0012] However, the presently available monopole antennas used in airborne platforms are highly prone to vibration, shock and thermal changes. Further, the antennas are available with complex geometry, increase in size with limited bandwidth.
[0013] Therefore, there is a need in the art with compact rugged monopole patch antenna for airborne data link radio communication and to solve the above-mentioned limitations.
SUMMARY OF THE INVENTION

[0014] An aspect of the present invention is to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below.
[0015] Accordingly, in one aspect of the present invention relates to a monopole patch antenna (100, 200) for airborne data link radio communication. The antenna comprising: at least one printed patch (110, 210) with an extended edge feed section (120, 220) of length L1, wherein a structure of the edge feed section of the printed patch is tapered from a first width W1 to a second width W2 after the length of L1, at least one metal back plate (230), wherein the printed patch with the extended edge feed section is attached to the metal back plate via fasteners/connectors, at least one transparent radome cover (240) configured to enclose the metal back plate, at least one bottom supporting plate (250) acting as a base support for the transparent radome cover, the metal back plate and the printed patch, wherein the printed patch is screwed to the bottom supporting plate and at least one RF connector (260) configured to couple with the printed patch via a slot in the extended edge feed section.
[0016] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[0017] The detailed description is described with reference to the accompanying figures.
[0018] Figure 1 shows a structure of Monopole Patch Antenna according to an exemplary implementation of the present disclosure/ invention.
[0019] Figure 2 shows a simulation model of designed Monopole Patch antenna with (a) Metal back plate (b) With metal back plate and radome according to an exemplary implementation of the present disclosure/invention.
[0020] Figure 3 shows return loss of monopole patch antenna in all configurations according to an exemplary implementation of the present disclosure/invention.
[0021] Figure 4 shows radiation pattern of Monopole Patch antenna at Phi(Ø) according to an exemplary implementation of the present disclosure/invention.
[0022] Figure 5 shows return loss variation of Monopole Patch antenna with different sizes / shapes of metal plates according to an exemplary implementation of the present disclosure/invention.
[0023] Figure 6 shows return loss of final optimized Monopole Patch antenna according to an exemplary implementation of the present disclosure/invention.
[0024] Figure 7 shows radiation pattern (φ =0 and φ =90 plane) of Monopole Patch antenna with rectangular plate and PTFE radome cover at (a) 4.5 GHz, (b) 6 GHz and (c) 8.54 GHz according to an exemplary implementation of the present disclosure/invention.
[0025] Figure 8 shows simulated realized gain of Monopole Patch antenna rectangular base plate according to an exemplary implementation of the present disclosure/invention.
[0026] Figure 9 shows realized Monopole Patch antenna (a) With circular base plate antenna and Glass epoxy radome (b) Rectangular shape metal base plate antenna with hard PTFE radome according to an exemplary implementation of the present disclosure/invention.
[0027] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative methods embodying the principles of the present disclosure. Similarly, it will be appreciated that any flow charts, flow diagrams, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.
DETAILED DESCRIPTION OF THE INVENTION
[0028] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
[0029] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
[0030] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces.
[0031] By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.
[0032] Figures discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way that would limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged communications system. The terms used to describe various embodiments are exemplary. It should be understood that these are provided to merely aid the understanding of the description, and that their use and definitions in no way limit the scope of the invention. Terms first, second, and the like are used to differentiate between objects having the same terminology and are in no way intended to represent a chronological order, unless where explicitly stated otherwise. A set is defined as a non-empty set including at least one element.
[0033] In the following description, for purpose of explanation, specific details are set forth in order to provide an understanding of the present disclosure. It will be apparent, however, to one skilled in the art that the present disclosure may be practiced without these details. One skilled in the art will recognize that embodiments of the present disclosure, some of which are described below, may be incorporated into a number of systems.
[0034] However, the systems and methods are not limited to the specific embodiments described herein. Further, structures and devices shown in the figures are illustrative of exemplary embodiments of the presently disclosure and are meant to avoid obscuring of the presently disclosure.
[0035] It should be noted that the description merely illustrates the principles of the present invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present invention. Furthermore, all examples recited herein are principally intended expressly to be only for explanatory purposes to help the reader in understanding the principles of the invention and the concepts contributed by the inventor to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof.
[0036] Various embodiments of the Monopole Patch Antenna system for airborne data link radio communication are further described with reference to FIG. 1 to FIG. 9.
[0037] The present invention discloses a Monopole Patch Antenna for airborne data link radio communication, in which at least some embodiments of the present disclosure can be implemented. Although the Monopole Patch Antenna (100) is depicted to include one or a few components arranged in a particular arrangement in the present disclosure, it should not be taken to limit the scope of the present disclosure.
[0038] The Monopole Patch Antenna (100, 200) is hereinafter interchangeably referred to as “Patch Antenna”, “printed monopole patch antenna”, “antenna”.
[0039] The present invention “printed monopole patch antenna has a wide band (4 GHz) of operation from 4.5 to 8.54 GHz. The present invention antenna is quite suitable for the handheld data link transmitter module due to its slim and compact size. The present antenna has a rugged structure and is suitable for all airborne applications where it will be subjected to high vibration, shock and thermal changes.
[0040] In one embodiment, the present invention antenna is light weight compact in size and fits into a set of shaped (Cylindrical, Rectangular and other shapes) radomes.
[0041] In one embodiment, the present invention antenna is built with monopole patch structure and is rugged, so that it is suitable for all terrain use.
[0042] In one embodiment, the present invention antenna is very compact and useful to establish data transmission link even between outbound and inbound mounting mechanism on any airborne platform. Stable omnidirectional pattern makes it a suitable candidate during manoeuvring also. There is no distortion of patterns with the mechanical fittings like base plate, set of screws, fasteners, radome etc.
[0043] In one embodiment, the present invention antenna complies with IP65 water proofing standard and is very easy to produce with very low cost.
[0044] In one embodiment, the present invention antenna finds application across all the airborne platforms, where the size and weight are critical.
[0045] In one embodiment, the present invention antenna design is unique, and the pilot may fix the antenna to his clothes and the performance is consistent. It is designed in such a way to have almost null effect of ground plate and other mounting structures.
[0046] In one embodiment, the construction of a micro strip fed compact wide band rugged monopole patch Antenna for airborne applications is an innovative idea for air borne communications. This present invention covers the design of rugged monopole patch antenna with almost zero effect due to presence of metallic back plate and radome cover in a very close vicinity of antenna element. The antenna is very compact, lightweight and achieved VSWR bandwidth of 62.1 % (4 GHz) around centre frequency of 6.5 GHz. A mechanical supportive structure and radome construction/design is optimized to achieve compact size and ruggedness in the structure so that module qualifies for stringent airborne environmental condition. The construction proposed in this antenna development and its topology can be used for construction and development of UWB, compact Omni-directional antenna for any airborne platform.
[0047] The present invention discloses a construction/design of the Compact Rugged Monopole Patch Antenna for airborne data link radio communication. The monopole patch antenna of the present invention comprises of proprietary monopole patch PCB, RF connector, transparent rectangular or cylindrical radome, base plate, fasteners, screws, etc.
[0048] Figure 1 shows structure of Monopole Patch Antenna according to an exemplary implementation of the present disclosure/ invention.
[0049] The figure shows the structure of Monopole Patch Antenna (100). In one embodiment, the Monopole Patch Antenna (100) comprises at least one printed patch (110, 210) with an extended edge feed section (120, 220) of length L1, wherein a structure of the edge feed section of the printed patch is tapered from a first width W1 to a second width W2 after the length of L1 and at least one metal back plate (230), wherein the printed patch with the extended edge feed section is attached to the metal back plate via fasteners/connectors.
[0050] In an embodiment, the antenna has been designed using the rectangular patch in monopole configuration. The monopole configuration provides impedance matching over a wide range of frequencies. The initial Length (LP) and width (WP) of the patch has been determined. To improve the impedance matching and current distribution over the desired range the edge feed was tapered from W1 to W2 after length of L1 for better impedance matching between feed and patch. Experimentation has been done to optimize ground dimensions, slit size of patch as well as above variables to achieve broad impedance bandwidth.
[0051] In an example embodiment, figure 1 shows the geometry of the rectangular ring slot printed monopole patch antenna. This structure is simulated on a dielectric substrate of Roger 5880 with length over all dielectric dimension of 21 x 18 x 0.8 mm3 (0.456λg*0.391λg*0.017λg). An Input line width is fixed to 1.6 mm which is 50 Ω for 0.8 mm thick substrate having relative permittivity of 2.2.
[0052] Figure 2 shows a simulation model of designed Monopole Patch antenna with (a) Metal back plate (b) With metal back plate and radome according to an exemplary implementation of the present disclosure/invention.
[0053] The figure shows the simulation model of designed Monopole Patch antenna with (a) Metal back plate (b) With metal back plate and radome.
[0054] In one embodiment, the monopole patch antenna comprises at least one printed patch (110, 210) with an extended edge feed section (120, 220) of length L1, wherein a structure of the edge feed section of the printed patch is tapered from a first width W1 to a second width W2 after the length of L1, at least one metal back plate (230), wherein the printed patch with the extended edge feed section is attached to the metal back plate via fasteners/connectors, at least one transparent radome cover (240) configured to enclose the metal back plate, at least one bottom supporting plate (250) acting as a base support for the transparent radome cover, the metal back plate and the printed patch, wherein the printed patch is screwed to the bottom supporting plate and at least one RF connector (260) configured to couple with the printed patch via a slot in the extended edge feed section. The monopole patch antenna further comprising PCB fixing screws screwed to the bottom metal plate and connector fixing screws screwed to bottom metal plate for supporting and strengthening. The monopole patch antenna further comprises a radome fixing screws provided at the bottom side of rectangular plate to withstand vibration requirements.
[0055] In an embodiment, the printed patch structure is simulated on a dielectric substrate with length over all dielectric dimension of 21 x 18 x 0.8 mm3 (0.456λg*0.391λg*0.017λg). The printed patch is a rectangular slot printed patch or a circular slot printed patch.
[0056] In one embodiment, the transparent radome cover is a transparent rectangular radome cover or a transparent circular radome cover. The transparent radome cover of the present invention is made with Glass epoxy (𝜖r = 4.4) and PTFE (𝜖r = 2.1).
[0057] The bottom supporting plate is in rectangular shape or in circular shape. The surface area of the bottom supporting plate is reduced to minimize the effect of metallic structures near the monopole patch antenna on the radiation patterns.
[0058] In one embodiment, the designed antenna is compact in size with 11 x 24 x 26 mm dimensions which is almost 67 % less compared to the existing monopole patch antennas. The antenna is very light weight (<20 grams) including the termination connector and radome. The design of printed monopole patch antenna with high VSWR bandwidth of 4.5- 8.54 GHz with appeared feed line.
[0059] In one embodiment, a length of the extended edge feed section is “L3” and a width of the printed patch is “Wp”, and wherein the length “L3” of the extended edge feed section and the width “Wp” of the printed patch are adjustable to achieve better radiation pattern. The designed antenna withstands high vibration, mechanical and thermal shock environment suitable for fitment in any type of aircraft.
[0060] In general, case connector will be directly soldered to the monopole patch antenna input without any supporting structure. But in the present invention, as per the application designed, the antenna has to withstand airborne standard applied to it. The designed antenna needs to be ruggedized and should be covered by a suitable radome cover. The bottom supporting plate is designed to which monopole patch can be screwed as well as it will provide support for screwing any kind of connector. This plate also provides a base for radome cover which is needed for protecting antenna from another environment.
[0061] The designed antenna is simulated in CST 2020. The simulation results show return loss better than 10 dB from 4.5 to 8.54 GHz. In the same structure, the metal base plate with the PCB fixing screws as well as connector fixing screws has been added as shown in Figure 2 (a). In the final stage simulation has been done with FRP radome cover and its fixing screws as shown in Figure 2 (b).
[0062] In the present invention, an impedance adjustment of tapered feed line through a definite shape for obtaining the wide bandwidth (BWR>2) and retaining the omnidirectional characteristics.
[0063] The present invention achieves a gain flatness of 1 dB across 3 GHz bandwidth with cross polarization level below 15 dB.
[0064] The present invention reduces the effect of metallic structures near the monopole patch antenna element on the radiation patterns (distortion less than 0.1 dB at peak) by reducing the bottom side plate surface area.
[0065] The present invention achieves beam symmetry by placing the ground plane near connector to have maximum beam coverage that helps during maneuvering of aircraft. The present invention maintains the radiation patterns, low insertion loss and other antenna parameters for two types of radome shapes (Cylindrical, Rectangular and any other shapes). The achieved insertion loss is <0.2 dB.
[0066] In one embodiment, the present invention antenna is tested for vibration of 0.14g2 /Hz in all three axis, thermal shock and ESS (-40 to +71°C, 10 cycles), rain test as per (IP-65) and bump test. All these tests are done as per MIL-STD-810E. Any efforts to provide mechanical strength to monopole patch antenna structure show adverse effect on radiation characteristics and VSWR due to disturbance in formation of multimode in the structure.
[0067] Figure 3 shows return loss of monopole patch antenna in all configurations according to an exemplary implementation of the present disclosure/invention.
[0068] The figure shows return loss of monopole patch antenna in all configurations i.e., monopole antenna, monopole antenna with metal back plate, monopole antenna with metal back plate and radome cover. A comparative result of all this structure is shown in Figure 3. From the results it is observed that added metal back plate has disturbed the multimode formation in the designed monopole patch antenna as a result antenna exhibits narrow band of operation. Also, the frequency of operation is shifted to the lower side due to the addition in electric length of antenna. While adding radome cover furthermore shift in frequency as well as matching of antenna degraded as radome cover is kept very close in order to maintain the small size. Due to the presence of radome in near reactive field it will cause inductive loading.
[0069] Figure 4 shows radiation pattern of Monopole Patch antenna at Phi(Ø) according to an exemplary implementation of the present disclosure/invention.
[0070] The figure shows the radiation pattern of Monopole Patch antenna at Phi(Ø). The radiation pattern in Omni-directional plane is shown in all three conditions as shown in Figure 4, i.e., monopole antenna, monopole antenna with metal back plate, monopole antenna with metal back plate and radome cover. After adding the metal back plate and radome, the radiation pattern shows significant degradation in omnidirectional characteristics and radiation efficiency of the designed antenna. From the detailed simulation of complete antenna structure, it is clear that designed antenna has to be optimized to overcome the loading effect of radome and metal back plate.
[0071] Figure 5 shows return loss variation of Monopole Patch antenna with different sizes / shapes of metal plates according to an exemplary implementation of the present disclosure/invention.
[0072] The figure shows the return loss variation of the monopole patch antenna with different sizes / shapes of metal plates. The figure shows the effect of dimension of bottom metal plate on return loss. The effect of back metal plate can be minimized by reducing the bottom side plate surface area. Due to the planner rectangular geometry of antenna rectangular shape back plate is designed which can cater our fixing requirement as well as cover less area behind the monopole patch antenna. The figure 9 (b) shows the designed rectangular metal plate also to address requirement of IP65 water leak proofing flat gasket provision is provided.
[0073] In an embodiment, the monopole patch antenna parameters need to modify the effect of metal base plate and radome. The antenna parameter L1, L2 will shows significant effect in reducing the electrical length of antenna. The design parameters L3 and Wp are tuned to achieve better radiation pattern with complete structure. The figure 6 shows return loss of final optimized Monopole Patch antenna. It is observed from the return loss characteristics of both the geometry shown in figure 6, that rectangular back plate will provide better matching for complete band of operation from 4.5 GHz to 8.54 GHz.
[0074] Figure 7 shows radiation pattern (φ =0 and φ =90 plane) of Monopole Patch antenna with rectangular plate and PTFE radome cover at (a) 4.5 GHz, (b) 6 GHz and (c) 8.54 GHz according to an exemplary implementation of the present disclosure/invention.
[0075] Figure 8 shows simulated realized gain of Monopole Patch antenna rectangular base plate according to an exemplary implementation of the present disclosure/invention.
[0076] The present invention is linearly polarized and shows stable omnidirectional radiation pattern in azimuthal plane with 2.2 dBi ±1 dB gain as shown in Figure 8 and beam-width of 94 degree in elevation plane shown in Figure 7. The cross-polarization level is better than 15 dB, which shows that antenna is having fairly linear polarization.
[0077] The radiation pattern of rectangular geometry is shown in figure 8 at three frequency 4.5 GHz, 6 GHz and 8.54 GHz. The simulation results shows omnidirectional pattern in azimuthal plane (Phi=0) with cross-polarization level ≥ 20dB.In elevation plane (Phi=90) shows 3 dB beam width of 94° (42° each side) with low cross-polarization levels.
[0078] Figure 9 shows realized Monopole Patch antenna (a) With circular base plate antenna and Glass epoxy radome (b) Rectangular shape metal base plate antenna with hard PTFE radome according to an exemplary implementation of the present disclosure/invention.
[0079] The figure shows realized Monopole Patch antenna (a) with circular base plate antenna and Glass epoxy radome (b) rectangular shape metal base plate antenna with hard PTFE radome.
[0080] As per the simulation result, the antenna and its associate items are developed. The rectangular antenna has the dimension of 11x24x26 mm and circular one has dimension of 16(D) x 29 mm. The figure 9 (a) shows the monopole patch antenna with circular metal back plate and Figure 9 (b) represents monopole patch antenna with rectangular metal back plate. Patch Printed circuit board has been manufactured for both the types of requirements with substrate having thickness of 0.8mm and permittivity of 2.2. The transparent radome cover is made with Glass epoxy (𝜖r = 4.4) and PTFE (𝜖r = 2.1). The radome cover with low permittivity material provided better results as the radome cover is in the near field range of antenna. The radome fixing screws are provided at the bottom side of rectangular plate to minimize their effect.
[0081] The present invention Rugged monopole patch antenna is designed/constructed and developed for airborne applications. The antenna design topology is discussed and ruggedized the antenna with associated items. The effects of metal back plate and radome cover are analyzed. The optimization techniques are applied to minimize these effects by modification in antenna design and mechanical design. As a result, the present invention rugged antenna finds use in any harsh environmental condition and fulfil requirement of airworthiness.
[0082] The technical advantages of the present invention antenna are provided below:
[0083] VSWR Bandwidth – Result shows the VSWR bandwidth of 4.5- 8.54 GHz for |S11|≤ -10 dB from Figure 6.
[0084] The present invention is linearly polarized and shows stable omnidirectional radiation pattern in azimuthal plane with 2.2 dBi ±1 dB gain as shown in Figure 8 and beam-width of 94 degree in elevation plane shown in Figure 7. The cross-polarization level is better than 15 dB, which shows that antenna is having fairly linear polarization. The antenna is subjected to all environmental specifications and observed satisfactory results.
[0085] The various embodiments described above are specific examples of a single broader invention. Any modifications, alterations or the equivalents of the above-mentioned embodiments pertain to the same invention as long as they are not falling beyond the scope of the invention as defined by the appended claims. It will be apparent to a person skilled in the art that the monopole patch antenna may be provided using some or many of the above-mentioned features or components without departing from the scope of the invention. It will be also apparent to a skilled person that the embodiments described above are specific examples of a single broader invention which may have greater scope than any of the singular descriptions taught. There may be many alterations made in the invention without departing from the spirit and scope of the invention.
[0086] Figures are merely representational and are not drawn to scale. Certain portions thereof may be exaggerated, while others may be minimized. Figures illustrate various embodiments of the invention that can be understood and appropriately carried out by those of ordinary skill in the art.
[0087] In the foregoing detailed description of embodiments of the invention, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the invention require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby incorporated into the detailed description of embodiments of the invention, with each claim standing on its own as a separate embodiment.
[0088] It is understood that the above description is intended to be illustrative, and not restrictive. It is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined in the appended claims. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein,” respectively.
, Claims:

1. A monopole patch antenna (100, 200) for airborne data link radio communication, the antenna comprising:
at least one printed patch (110, 210) with an extended edge feed section (120, 220) of length L1, wherein a structure of the edge feed section of the printed patch is tapered from a first width W1 to a second width W2 after the length of L1;
at least one metal back plate (230), wherein the printed patch with the extended edge feed section is attached to the metal back plate via fasteners;
at least one transparent radome cover (240) configured to enclose the metal back plate;
at least one bottom supporting plate (250) acting as a base support for the transparent radome cover, the metal back plate and the printed patch, wherein the printed patch is screwed to the bottom supporting plate; and
at least one RF connector (260) configured to couple with the printed patch via a slot in the extended edge feed section.

2. The antenna as claimed in claim 1, wherein the printed patch structure is simulated on a dielectric substrate with length over all dielectric dimension of 21 x 18 x 0.8 mm3 (0.456λg*0.391λg*0.017λg).

3. The antenna as claimed in claim 1, wherein an input line width of the antenna is fixed to 1.6 mm which is 50 Ω for a 0.8 mm thick substrate having relative permittivity of 2.2.

4. The antenna as claimed in claim 1, wherein the printed patch is a rectangular slot printed patch or a circular slot printed patch.

5. The antenna as claimed in claim 1, wherein the transparent radome cover is a transparent rectangular radome cover or a transparent circular radome cover.

6. The antenna as claimed in claim 1, wherein the bottom supporting plate is in rectangular shape or in circular shape.

7. The antenna as claimed in claim 1, wherein the transparent radome cover is made with Glass epoxy (𝜖r = 4.4) and PTFE (𝜖r = 2.1).

8. The antenna as claimed in claim 1, wherein a surface area of the bottom supporting plate is reduced to minimize the effect of metallic structures near the monopole patch antenna on the radiation patterns.

9. The antenna as claimed in claim 1, wherein the antenna is having a size of 11 x 24 x 26 mm dimension and a weight of about 20 grams.

 
10. The antenna as claimed in claim 1, wherein a length of the extended edge feed section is “L3” and a width of the printed patch is “Wp”, and wherein the length “L3” of the extended edge feed section and the width “Wp” of the printed patch are adjustable to achieve better radiation pattern.