Description:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

Complete Specification
(See section 10 and rule 13)

1. Title of the Invention: Conformal Log Periodic Array Antenna with rectangular patch top loading for Multi Band Applications

2. Applicant Name : 1. Andhra University
Nationality : India
Address : Visakhapatnam, AP, India -530003

3. Preamble to the Description :

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

DESCRIPTION
Field of the invention
This invention is related to antenna radiation system, more specifically, a single and compact antenna is conformal at 300, 450 and 600 angles. At 300 bending the proposed antenna produces more resonant frequencies. This antenna can be used in DCS, WLAN, WiMAX, Wi-Fi, point-to-point, fixed satellite and radio navigation and location applications
Background of the invention
The antenna should be flexible, conformal, and adaptable to curved surfaces and dynamic motions due to a variety of applications, including wearable technology, car navigation systems, medical microwave radiometry, health monitoring, and clinic treatment devices. The advantages of conformal antennas over conventional constructions include their light weight, simplicity in packaging for small quantities, and flexibility in adjusting the deployment method to alter the performance parameters of the antenna.
Due to their wide bandwidth, high gain, and planar design, planar log-periodic dipole array (LPDA) antennas are frequently utilised in a variety of communication applications. However, it is frequently impractical to integrate rigid substrates onto curved surfaces. Flexible substrates are the answer to this, therefore. Numerous flexible substrates have already been studied. Few investigations of the conformal LPDA have so far been published. The author in presents a highly bendable log-periodic array antenna for flexible electronics. Measurements of the radiation and reflection patterns show this antenna's adaptability for three different radii in both convex and concave forms, including 50, 30, and 10 mm. For use with conformal load-bearing antenna structures (CLASs), a broadband high-gain bi-layer log-periodic dipole array (LPDA) is introduced. The two LPDA layers are printed on various thin dielectric substrates that are largely isolated from one another. A wide conformal quasi-printed Log Periodic dipole band-notched antenna is introduced. The researchers demonstrated a conformal log-periodic balloon antenna that operates in the very high-frequency (VHF) band. This antenna consists of eight conformal bowtie-dipole elements that are cross-fed by a parallel-strip transmission line. A wideband periodic cylindrical conformal fork-shaped antenna is designed for wireless, point-to-point and WiMAX applications.
Additionally, a lot of antennas today are appropriate for multiband application. A small, multiband Kapton-based inkjet-printed antenna for flexible wireless devices. For multiband DCS/Bluetooth/WLAN applications, a novel miniaturised cylindrical conformal microstrip antenna is designed for LTE, WLAN, and Wi-MAX applications, a multiband slotted log periodic dipole array antenna design using Giuseppe Peano fractal geometry is presented.
Feed Arrangement:
For sustaining a project occasional dipole reception apparatus legitimately there are various challenges that are faced. There are a number of factors on which feed impedance is dependent upon. To control this we can alter the dividing, and consequently the impedance for the feeder which unite both of the dipole parts mutually. Indeed, even subsequent to altering the separating impedance differs with recurrence. We overcome the same to a substantial degree by utilizing the more extended components made out of a bigger width pole. Indeed, even in the wake of doing the aforementioned steps it may happen that the last sustain impedance doesn’t typically equal to 50 ohm without anyone else. It is an ordinary wonders and a further type of impedance coordinating is to be connected. This should be possible by applying a stub or even a transformer. Determination of the system to be utilized will rely on upon the reception apparatus' use and its recurrence range. Electromagnetic Waves and Antenna Basics As the radio signs are a sort of electromagnetic wave, and as they are the way in which radio signs transmit, they have a huge bearing on RF gathering mechanical assemblies themselves and as well as the RF antenna design. Aside from the distinction in their wavelength and recurrence electromagnetic waves are the same sort of radiation as light, ultraviolet and infrared beams. EM waves forces both electric and attractive parts which are conjoined. The planes for these field are at right indicates each another and to the heading of progress of the wave. The voltage change happening in the radio frequency which is transmitting the sign produces electric field, and the present stream is because of the attractive changes. According to the test perceptions It is noticed that the lines of force in the electric field continue running along the same turn as the radio frequency wave receiving wire, and spreads out while they move a long way from it. Estimation of electric field is done in regards to the change of potential over a given partition, e.g. volts per meter, and is allocated as the field quality. Moreover when radio wave gets a banner the electric field changes cause the voltage changes on the reception apparatus and the attractive changes cause a present stream. Among the major property of a wavefirst is it wavelength. It is characterized as the separation among a top on one wave to the indistinguishable top on the following wave. For less demanding estimation the best indicates pick is the top as this can be effectively recognized, however any Point-is worthy.

Existing Method Limitations
The existing models supports single band and dual band applications. 1. Not useful for the multiple applications.
2. Not suitable for the synthetic aperture radar applications
3. The limited gain of the existing models does not permit its use in portable devices.
4. Low VSWR is also a limitation of the existing model.
5. The existing antenna produces poor radiation characteristics at 300 bending angle.

Need for the Invention
a. A planar and conformal log periodic dipole array antenna design is needed to reduce both of the profile height and the transverse size
b. This proposed antenna possesses a much wider impedance bandwidth with nearly the same profile height. Moreover, higher radiation efficiency is greatly improved
c. The design of a multiband antenna is generally be useful in an equipment which have many applications.
Summary of the invention
The Conformal Log Periodic Antenna Array with rectangular patch top loading for Multi Band Applications is designed and corresponding prototype is fabricated. Initially a planar PLPDA antenna with rectangular patch top loading is designed and then it is conformed at 300, 450 and 600 angles. The proposed invention shows the planar and conformal PLPDA with rectangular patch top loading. This antenna contains 6 dipole elements, and those are fabricated on both sides of the substrate along with feed line. In this configuration top of each dipole element is attached to the rectangular patch.
In this invention, a Planar and conformal LPDA antenna with rectangular patch top loading for multiband applications is designed. Same is fabricated on a polyimide substrate. At 300 bending the proposed antenna produces more resonant frequencies, those are 1.8GHz, 3.5GHz, 5.8GHz, 7.5GHz and 9.3GHz with gain values of 11.8dBi, 2dBi, 9.26dBi, 8.99dBi and 9.6dBi respectively. The proposed planar and conformal models have a return loss of below -10 dB over the specified resonant frequencies and maintain VSWR ≤ 2.
The proposed antenna is compact in size and therefore, the proposed antenna can be used in DCS, WLAN, WiMAX, Wi-Fi, point-to-point, fixed satellite and radio navigation and location applications. The result shows a good correlation between the measured and the simulation results.
Detailed description of the invention
Description of the PLPDA with rectangular patch top loading
In this work initially a planar PLPDA antenna with rectangular patch top loading is designed and then it is conformed at 300, 450 and 600 angles. The planar and conformal PLPDA with rectangular patch top loading. This antenna contains 6 dipole elements, and those are fabricated on both sides of the substrate along with feed line. In this configuration top of each dipole element is attached to the rectangular patch. Basically this antenna is designed as per the carrel method but here in addition to that Multi tau technique is employed that means it uses variable tou (τ) values. Initially the design parameters τ=0.87 and σ=0.16 are considered for getting 7dB gain. Then for getting optimized dimensions considered variable tou values of τ1 =0.875, τ2 =0.857, τ3 =0.833, τ4 =0.8 and τ5 =0.75. Therefore the lengths of the LPDA antenna elements are calculated by Ln+1=Ln x τn and the lengths of the antenna are represented. This antenna uses uniform width and spacing between the elements and the values are width W=2mm and spacing S=4mm. In addition to that S1= 9mm, S2= 3mm and length and width of the rectangular patch are chosen as 3mm and 2mm for all the elements. The total dimensions of all the antennas are 44mm x 40mm.
The present LPDA Wideband systems are favored due to the low power and high data rate transmissions in the 2-8GHz frequency range. In this frequency range, it exhibits high impedance matching and minimal signal distortion. A larger bandwidth permits the transmission of large amounts of data. Conventional Microstrip antennas are suited for several wireless applications due to their inexpensive cost, compact size, and low weight. These components are simple to combine with RF front-end hardware. However, a microstrip antenna's shortcomings include a restricted bandwidth, poor gain, low efficiency, strong cross-polarization of radiation fields, and the propagation of surface waves in the dielectric substrate. Using a microstrip log-periodic antenna can assist in overcoming these limitations. Microstrip Log-periodic antenna consists of a series of parallel, side-by-side linear dipoles arranged in a coplanar array with numerous log-periodic-shaped components. LPDA are a strong candidate for UWB transmitting and receiving applications because to their enhanced bandwidth and gain. Numerous properties of log-periodic antennas may be utilized to create reconfigurable designs with compact footprints, cost-effective designs, and broadband applications. The microstrip frequency reconfigurable log-periodic dipole patch array utilized in this study is designed for wideband operation in the S-band and C-band sectors. It has appropriate UWB gain and directivity qualities. WLAN and WiMAX are the principal wireless communication applications. Bluetooth, Hiper Lan, and IEEE 802.11 all operate in the radio frequency spectrum's S-band (2-4 GHz) and C-band (4-8 GHz). Many real-time systems therefore benefit from the design of the (2-8GHz) frequency spectrum. Several Log-periodic antennas are employed to build UWB antennas, but a frequency LPDA with switching between bands and resonant frequencies in the S- band (2-4 GHz) and C- band (4- 8 GHz) is unique.
Using RF-Switches such as PIN diodes, MEMS, and Varactors, a reconfigurable system may alter the patch area's current distribution. Regarding traditional LPDA, so many authors are mentioned in the literature. However, it is challenging to construct Reconfigurable LPDA to provide switching of frequency, pattern, and polarization properties for current wireless communication. This project aims to produce a frequency-configurable LPDA with good radiation characteristics between 2 and 8 GHz to cover the C- and S- bands.

Description of Drawings
Figures 1 shows inset fed single patch antenna along with its dimensions. This figure also shows the layout of bottom plate and top plate as well. Figure 2 represent the simulation design of t inset fed single patch antenna with DGS. Also, it represent the antenna printed on a flexible substrate. It replicates the actual model of figure1. Figures 3 is the front view of the proposed model (E-shaped Inset fed Patch antenna in a 2x2 array). Figure 4 shows the back view of the E-shaped Inset fed Patch antenna with DGS proposed in a 2x2 array which also show the location of elements on the other side. Figure 5shows the (a) Front view of the fabricated patch antenna, (b) Back view of the fabricated patch antenna (c) Patch antenna connected to combinational analyser for measurements . The antenna is made on a rectangular substrate measuring 4.5cm x 4 cm. The size of the patch allows its application in the portable devices. Figure 6 represents the return loss in both the case of simulation and physical measurement. The four graphs representing the simulated and measured return loss of the flexible patch at various bending angles viz (a) Planar (b) 30° (c) 45° (d)60°. It is observed that both simulated and measured results are in close agreement. Figure 7 representing Measured and Simulated VSWR for planar and conformal models at viz (a) Planar (b) 30° (c) 45° (d)60°. Figure 8, 9 and 10 show the radiation pattern of Planar mode E & H plane patterns at 5.8GHz, 7.5GHz, and 9.3GHz respectively. Figure 11 shows the gain of planar and conformal models of the proposed patch antenna.

, Claims:CLAIMS
We claim:
(i) A Planar and conformal LPDA antenna with rectangular patch top loading for multiband applications is designed.
(ii) At 300 bending the proposed antenna produces more resonant frequencies, those are 1.8GHz, 3.5GHz, 5.8GHz, 7.5GHz and 9.3GHz with gain values of 11.8dBi, 2dBi, 9.26dBi, 8.99dBi and 9.6dBi respectively.
(iii) The proposed planar and conformal models have a return loss of below -10 dB over the specified resonant frequencies and maintain VSWR ≤ 2.
(iv) The proposed antenna is compact in size and therefore, the proposed antenna can be used in DCS, WLAN, WiMAX, Wi-Fi, point-to-point, fixed satellite and radio navigation and location applications.

Swetha Velicheti, Pavada Santosh, Dr. P. Mallikarjuna Rao, Dr.M.Satya Anuradha
Dated this 23rd February 2023.