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

Title: A COMPACT HIGH-PERFORMANCE ANTENNA

APPLICANT DETAILS:
(a) NAME: Bharat Electronics Limited
(b) NATIONALITY: Indian
(c) ADDRESS: Outer Ring Road, Nagavara, Bangalore-560045, Karnataka, India

PREAMBLE TO THE DESCRIPTION:
The following specification (particularly) describes the nature of the invention (and the manner in which it is to be performed):
A COMPACT HIGH-PERFORMANCE ANTENNA

FIELD OF INVENTION:
The present disclosure/invention relates in general to antennas and more particularly to a compact high performance antenna.

BACKGROUND OF THE INVENTION:
The following background discussion includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication expressly or implicitly referenced is prior art.
In general, multiple antennas are used to operate for GPS, GLONASS and IRNSS navigation systems. Satellite navigation systems (GPS, GLONASS, and IRNSS) are used for tracking and location mapping in most of the aircraft carriers, ships, and automobiles. All Navigation satellites conventionally operate in the 1-2.5 GHz frequency band of operation.
GPS systems usually operate in three different bands i.e. L1, L2, L5 while IRNSS are in two bands i.e. L and S - band. Using Multiple antennas to satisfy the demand will increase the complexity and cost of system.
Some prior art on GNSS antenna is presented. For all the GNSS systems antenna performance is very critical. Lot of Work has been done on improving the performance of these antennas previously, some of them are listed below.
One of the prior art discloses a Compact Broadband Circularly Polarized crossed dipole antenna for GNSS Applications. This prior art antenna 10-dB impedance BW is 0.71 GHz (1.16 – 1.87 GHz), 3-dB axial 3 ratio bandwidth of 630 MHz for AR < 3 dB, from 1.24 – 1.87 GHz. This prior art antenna design achieves broad bandwidth, but it covers Galileo E1, E5, and E6 bands, L1 (1563-1587 MHz) band if GPS and, Half of L2 Band (1215-1239 MHz) of GPS.
Another prior art discloses dual–band 5 GPS antenna with horizontal polarization. This prior art antenna array is described herein that is suitable for dual band GPS reception. This prior art antenna is suitable for L1 and L2 of GPS Bands, polarization of the antenna is linear. This prior art antenna design achieves dual band operation, but its polarization is horizontal and due to that the power received by antenna will be 3 dB less than the CP antenna.
Another prior art discloses circularly polarized printed crossed-dipole antenna using branch-line feed network for GPS applications. This prior art discloses circularly polarized antenna structure composed of two printed dipoles located orthogonally, two printed baluns to feed the dipoles and a feed network connected to the baluns for global positioning system receivers. This prior art antenna has an impedance bandwidth of 950 MHz with S11 < -10 dB from 1260 MHz to 2210 MHz, 3- dB axial ratio bandwidth of 631 MHz for AR < 3 dB, from 1307 MHz to 1938 MHz and a maximum gain of 5.72 dBic. This prior art antenna design achieves broad bandwidth, but it is covering only m (GPS) L1 (1575 MHz) band.
Further prior art discloses a dual-band global positioning system antenna fed by the proximity-inset method. This prior art discloses a method to excite dual band for a micro-strip antenna on a two-layer substrate by combining the proximity feed and the inset feed. In this prior art achieved impedance bandwidths are 60 MHz centered at 1.215 GHz and 65 MHz centered at 1.563 GHz. The 3 dB axial-ratio bandwidths are 15 MHz centered at 1.228 and 20 MHz centered at 1.575 GHz. The overlapped return-loss and axial-ratio bandwidths are 10 MHz at both bands. Achieved peak gain is 1.4 dBic. The dimension of the antenna is 100 mm x 100 mm x 2.4 mm. This prior art antenna covers dual band in a compact height, but it suffers from low gain and its CP band width is also half of the required bandwidth for secure GPS communication.
Further prior art discloses a RIS-Based Compact Circularly Polarized Micros trip Antennas. This prior art antenna structure consists of a slotted-slit-micro strip patch on a Reactive Impedance Surface substrate for achieving circular polarization. The CP radiation with compact size is achieved by asymmetric\symmetric-slot-slit cut along the orthogonal\ diagonal directions of the patch radiator. This prior art antenna is having 10- dB return loss bandwidth of 5.2% (2.47–2.60 GHz) and 3-dB axial ratio bandwidth of 1.6% (2.51–2.55 GHz) with peak gain of 3.41 dBic. The overall antenna volume is on a low cost FR4 substrate. This prior art antenna covers only single band with very narrow CP bandwidth and Reactive Impedance Surface (RIS) has increased the complexity of design.
Therefore, there is a need in the art with a compact high-performance antenna to solve the above-mentioned limitations.

OBJECTIVES OF THE INVENTION:
The primary object of the present invention is to overcome the problem stated in the prior art.
Another object of the present invention is to provide a to a compact high-performance antenna.

SUMMARY OF THE INVENTION:
The present invention provides a compact high-performance antenna comprising:
a) a broadband circularly polarized dipole antenna with plurality of resonators (101, 102, 104), where plurality of strip dipoles, slot patches, and truncated patches is configured to achieve broadband circular polarization with better than 10 dB impedance matching.
In an embodiment, the coupling between the plurality of strip dipoles, slot patches, and truncated patches multiple circularly polarized resonant modes have been generated by the antenna to satisfy the need of broadband CP radiation.
In an embodiment, the four hollow metal columns are simulated with the antenna design to achieve the suspended structure without affecting the performance of antenna.
In an embodiment, the square ground plane (107) is employed with the height of H1 to achieve a directional radiation pattern for the antenna.
In an embodiment, the radome (106) is configured to provide protection to the antenna.
The present invention provides a method of operation of a compact high-performance antenna, comprising steps of:
a) implementing broadband circular polarization with better than 10 dB impedance matching by a broadband circularly polarized dipole antenna with plurality of resonators (101, 102, 104), where plurality of strip dipoles, slot patches, and truncated.

DETAILED DESCRIPTION OF DRAWINGS:
To further clarify advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of their scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings in which:
Fig. 1a: illustrates a top view of designed GNSS antenna.
Fig. 1b: illustrates a bottom view of designed GNSS antenna with radome and other fixtures.
Fig. 1c: illustrates shows a GNSS antenna with radome and other fixtures.
Fig. 2: illustrates a fabricated antenna model.
Fig. 3: illustrates shows graph of antenna characteristics variation over frequency (a) VSWR vs. Frequency and (b) Peak Gain vs. Frequency.

DETAILED DESCRIPTION:
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.
It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be restrictive thereof.
The terms “comprises”, “comprising”, “includes”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus proceeded by “comprises... a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or method.
The various embodiments of the present disclosure/invention describe a compact high performance antenna covering GPS, GLONASS, Galileo and IRNSS bands for secure communication.
In general, different satellite navigation systems are working on different inclination angles such as GPS is working on 55°, GLONASS is working on 64° and IRNSS is working on 19.2° for taking the advantages of different altitude locations. GLONASS has better coverage at higher altitudes. In most of the antennas axial ratio is < 3 dB over very narrow band i.e. there 3 dB axial ratio beam width is less and due to this, its sensitivity will reduce drastically over the horizon. Jamming of individual GPS (Global Positioning System), GLONASS (Global Navigation Satellite System), and IRNSS (Indian Regional Navigation Satellite System) receiver will be easy.
Antenna polarization is one of the most critical considerations when designing and installing a wireless network. CP antennas have been shown to be superior because they offer numerous performance advantages over traditional LP antennas. Circularly polarized radiation reduces multipath interference and provides flexibility in the orientation of antennas. Consequently, CP antennas have been used in wireless applications, such as GPS, GLONASS, and IRNSS. A multi-band or broadband circularly polarized with wide beam width can be used in all type of satellite navigation systems.
The present invention discloses a compact high performance antenna covering GPS (Global Positioning System), GLONASS (Global Navigation Satellite System), and IRNSS (Indian Regional Navigation Satellite System) bands for Secure Communication.
In an embodiment, the present invention provides a compact high-performance antenna comprising:
a) a broadband circularly polarized dipole antenna with plurality of resonators (101, 102, 104), where plurality of strip dipoles, slot patches, and truncated patches is configured to achieve broadband circular polarization with better than 10 dB impedance matching.
In an embodiment, the coupling between the plurality of strip dipoles, slot patches, and truncated patches multiple circularly polarized resonant modes have been generated by the antenna to satisfy the need of broadband CP radiation.
In an embodiment, the four hollow metal columns are simulated with the antenna design to achieve the suspended structure without affecting the performance of antenna.
In an embodiment, the square ground plane (107) is employed with the height of H1 to achieve a directional radiation pattern for the antenna.
In an embodiment, the radome (106) is configured to provide protection to the antenna.
In an embodiment, the present invention provides a method of operation of a compact high-performance antenna, comprising steps of:
a) implementing broadband circular polarization with better than 10 dB impedance matching by a broadband circularly polarized dipole antenna with plurality of resonators (101, 102, 104), where plurality of strip dipoles, slot patches, and truncated.
In one embodiment, the present invention provides design with compact and low-cost broadband antenna for multi-function applications.
In one embodiment, the present invention antenna is covering the bands of GPS, GLONAS, and IRNSS with rugged design making it suitable for all terrain use.
In one embodiment, the present invention antenna has high 3 dB Axial Ratio Beam width.
In one embodiment, there is no distortion of patterns with radome and other mechanical fittings like base plate, set of screws, fasteners etc.
In one embodiment, the present invention antenna complies with IP65 water proofing standard and is very easy to produce with very low cost.
In one embodiment, the present invention antenna finds application across all ground and Naval platforms.
In one embodiment, the present invention broadband circularly polarized (CP) antenna is developed which covers existing navigation frequency bands. This antenna can be fitted with all the available receiver systems.
In one embodiment, single antenna can be replaced in place of multiple antennas required for different Satellite navigation Systems.
In one embodiment, IRNSS and other navigation systems will be backup for secure communication in case of GPS intentional unavailability or selective availability.
The figure 1a shows a top view of designed GNSS (Global Navigation Satellite Systems) antenna according to an exemplary implementation of the present disclosure/ invention.
The figure 1b shows a bottom view of designed GNSS antenna with radome and other fixtures according to an exemplary implementation of the present disclosure/ invention.
The figure 1c shows a GNSS antenna with radome and other fixtures according to an exemplary implementation of the present disclosure/ invention.
A Computer Simulation Technology (CST) simulation model of broadband GNSS antenna with Radome covers and other fixing structures is shown in Fig. 1. The fabricated model and results are shown in Fig.2 and 3 respectively.
In one embodiment, several individual single band and multiband antennas have been developed to receive GPS L1, L2, and L3 signals, GLONASS signals, IRNSS L5, and S- band signals respectively. Some antennas have covered a small section of CP band within the mentioned bands, but these antennas are not useful for secure communication because it requires higher bandwidth to send data with secure protocols. System working with single band GNSS receivers are more prone to Jamming.
In the present invention, a broadband circularly polarized dipole antenna with multiple resonators (101, 102, 104) is proposed. The antenna is composed of strip dipoles, slot patches, and truncated patches for achieving broadband circular polarization with better than 10 dB impedance matching. By utilizing the coupling between the elements multiple circularly polarized resonant modes have been generated to satisfy the need of broadband CP radiation. In addition, four hollow metal columns are simulated with the antenna design to achieve the suspended structure without affecting the performance of antenna. A square ground plane (107) is employed with the height of H1 to achieve a directional radiation pattern and radome (106) is employed to provide protection.
An innovative GNSS antenna is designed and developed for worldwide available GNSS frequency bands. Multiple techniques are used to realize broadband circular polarization with higher beam widths. Effects of radome and their position is optimized for required antenna performance over broadband. As a result, the proposed antenna finds use in any harsh environmental condition and fulfils requirement of different platforms.
Figure 3 shows graph of antenna characteristics variation over frequency (a) VSWR vs. Frequency and (b) Peak Gain vs. Frequency.
The proposed antenna shows the following results-
Voltage Standing Wave Ratio (VSWR) Bandwidth – Result shows the achieved 2:1 VSWR bandwidth is ~ 2 GHz from Figure 3(a).
The present invention designed antenna shows 86 % CP Bandwidth with more than 3dBic average gain over the band.
The antenna is subjected to all environmental specifications and observed satisfactory results.
In one embodiment, the present invention discloses compact high performance antenna covering GPS, GLONASS, Galileo and IRNSS bands for Secure Communication, for achieving the enhanced coverage at all altitudes, comprising of: - an air suspended dielectric substrate with metallic back plate, half section of cross dipole is on top of substrate and half is on bottom of substrate, fed by Co-axial connector.
In one embodiment, the present invention antenna has an impedance bandwidth of 2 GHz with VSWR < 2 from 1 GHz to 3 GHz achieved through cascading of multi-resonator responses.
In one embodiment of the present invention, broad axial ratio BW of 1.5 GHz (1 -2.65 GHz) is achieved through cascading of multi resonator responses.
In one embodiment of the present invention, a half power axial ratio beam coverage of > 140° is achieved over the GPS, GLONASS, and Galileo band of operation by utilizing low gain design technique.
In one embodiment, the antenna is designed to meet all terrain applications for secure communication, achieved through fitment of multi band radome structure, ruggedization, sealing the exposed areas, etc.,
The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the substance of the invention may occur to person skilled in the art, the invention should be construed to include everything within the scope of the invention.
,CLAIMS:We Claim:

1. A compact high-performance antenna comprising:
a) a broadband circularly polarized dipole antenna with plurality of resonators (101, 102, 104), where plurality of strip dipoles, slot patches, and truncated patches is configured to achieve broadband circular polarization with better than 10 dB impedance matching.
2. The compact high-performance antenna as claimed in claim 1, wherein a coupling between the plurality of strip dipoles, slot patches, and truncated patches multiple circularly polarized resonant modes have been generated by the antenna to satisfy the need of broadband CP radiation.
3. The compact high-performance antenna as claimed in claim 1, wherein at least four hollow metal columns are simulated with the antenna design to achieve the suspended structure without affecting the performance of antenna.
4. The compact high-performance antenna as claimed in claim 1, wherein a square ground plane (107) is employed with the height of H1 to achieve a directional radiation pattern for the antenna.
5. The compact high-performance antenna as claimed in claim 1, wherein a radome (106) is configured to provide protection to the antenna.