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: A Compact Inset-Fed 2x 2 E-Shaped Patch Antenna Array with and without DGS for High Frequency Multiband 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 2x2 array E-Shaped Microstrip Patch Antennas (MPA) for Ku, K and Ka band applications. This E-Shaped MPA is a very compact size for high frequency applications.
Background of the invention
In recent developments, Microstrip array antenna has been enhanced with different shapes and sizes to achieve wide bandwidth and high gain at high frequencies. The tri-band antenna design technology provides broadband assistance with high-speed internet access and high-quality satellite broadcasting [1]. In [2], the author suggested using a double-layer circular polarisation (CP) frequency selective surface (FSS) to transmit and receive Ka-band signals (17.3–20.2 GHz) and to reflect Ku band signals (11.7–12.75 GHz). This would preserve CP in both bands. For satellite television applications, a microstrip patch antenna loaded with two partially T-shaped slots is fed at a different position depending on the substrate's dielectric composition [3]. According to [4], an FSS is made to transmit electromagnetic waves (EM) in the K-band (18 to 21.6 GHz) and the Ka-band (29.3 to 32 GHz) at multiple angles of incidence that are all within 50 degrees for TE and TM polarizations. In the X-band, an experimental demonstration of a 2 x 2 antenna embedded with a DGS integrated array showed a 12 dB improvement in the isolation between co-pol and cross-pol radiations [5]. With a conventional dual-polarized array, a new tri-band planar antenna array with dual polarizations and a shared aperture is created. For possible synthetic aperture radar applications, the developed antenna is beneficial [6]. With a gain of 19.5 dBi and an operational frequency range of 15.6 to 17.3 GHz, a new patch antenna with two symmetrical slits and two closely spaced resonances has been developed [7]. It is useful for a variety of radar applications. To achieve wide bandwidth and high gain, a 4 × 4 element array is developed in the X-band and manufactured using the Direct Metal Laser Sintering technology [8]. For high gain and broad bandwidth applications, a compact 2x2 array E-shaped antenna with an RT duriod substrate is used in this work.
Existing Method Limitations
The existing models supports single band and dual band applicatios. 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.

Need for the Invention
a. An antenna with The findings demonstrated that the suggested 2x2 array antenna with DGS appears to have higher resonant frequencies with good return loss, better VSWR, high gain, and good bandwidth when compared to a single patch antenna is required for the needs of the future electronic gadgets.
b. A compact and less manufacturing complexity antenna design may help reduction in production time and cost of the overall system.
c. The design of a multiband antenna is generally be useful in an equipment which have many applications.
d. An array antenna suitable for satellite communications, space research, and radio navigation will have large demand.
Summary of the invention
In recent years, there has been a considerable increase in the need for wireless applications such as satellite communication, earth observation, remote sensing, and multifunction radar. These applications frequently require systems with different band capabilities and polarisations. Multiband antennas with various polarisations may significantly improve information content, resolution, and system efficacy in comparison to single-band, single-polarisation operation. As an example, synthetic aperture radar (SAR) must be outfitted with multiband antennas with dual polarisation in order to serve as a multipurpose sensor in all weather conditions and day/night. On the other hand, wireless communication systems must always be compact, lightweight, and economical. Multiple multiband antennas with dual polarisations have been reported over the previous two decades. In general, for multifunction radar applications, high frequency operation provides higher resolution images, although low frequency can overcome large obstructions and provide some information about the target's characteristics. Multiband operation can also improve the system's versatility, hence lowering the number of required platforms and the cost. Multiband array antennas are often required to share a single aperture in order to reduce the size, mass, and expense of the system. Due to the constraints of radiating components and the difficulty of creating feed networks for each band, this is always accompanied by major design challenges. This becomes considerably more challenging when dual polarisations are required and the number of feed networks increases by two. In addition, for large frequency ratio operations (L, C, X, Ku, and Ka band), the element spacing of various antenna arrays must vary in order to minimise grating lobes and maximise aperture efficiency. Several approaches have been presented to generate these arrays with shared apertures. The patches and spaces for C- and X-band activities are interwoven. The shapes of perforated and their variants were given. To manufacture shared-aperture dual-band dual-polarized arrays. In addition, the technology of interlacing the radiation elements of various bands has been widely implemented. The second challenging issue is fitting many feed networks of diverse bands and polarisations into a single aperture while maintaining a high level of isolation. This article describes a novel tri-band planar antenna array with dual polarisations and a shared aperture. The advantages of multiband operation in multifunction radar systems have been proved in real-world applications. Until now, the majority of published work has concentrated on dual-band operations, whereas tri-band operations have been the topic of a small number of studies. As feeds, SEASAT, Jason2/Jason3, and COWVR missions utilised tri-band and even five-band antennas. However, they were meant for radiometers and therefore utilised multifrequency horn antennas. Consequently, they are enormous, bulky, and costly. The only tri-band dual-polarized antenna for SAR applications, as far as the authors are aware. Compared to previously published studies, the proposed antenna offers a number of advantages: (1) This is the first dual-polarized shared-aperture array operating in the X/Ku/Ka frequencies. Higher frequencies are chosen due to the need for further size reduction and the integration with small platforms (small satellites or UAV); (2) the proposed antenna has a low profile, simplified structure and is therefore easy to assemble; (3) the proposed planar tri-band array has a very good geometrical symmetry, making it suitable to serve as the feed of reflector antennas; (4) the six feed networks for three bands and dual polarisations are carefully configured in a symmetrical manner; and (5) the proposed antenna is In this study, the transmit power is distributed among a large number of T/R modules, resulting in low power at each antenna element. Even if all three frequency bands operate simultaneously, no special high-power management requirements, such as multiplicator effects, are enforced. As an illustration of a space-based SAR application, we will not investigate other factors such as the impact of temperature on system performance. This document has the following structure: Configuration of the shared-aperture X/Ku/Ka-band array and the three radiation elements.
Detailed description of the invention
In this work the multiband E-Shaped Inset Fed Patch Antenna is designed to operate in Ku, K and Ka bands with an input of 50 ohms impedance using RT Duriod as a substrate with loss tangent , height = 1.575 mm, and . The proposed Inset-fed 2x2 array Antenna dimensions are computed using standard design equations [9].
(1)
(2)
(3)
(4)
(5)
III. Design parameters
The design equations presented in section II are used to compute the Inset-Fed E-Shaped Antenna dimensions, and the resulting optimized dimensions are displayed in table 1.
Dimensions of a single E-shaped inset-fed patch antenna are shown in Table 1.
Substrate Name RT Duriod 5880
Substrate length and Ground length 8.5mm
Substrate width and Ground width 7mm
Substrate height 1.575mm
Patch Length 6mm
Patch Width 4mm

Description of Drawings
Figures 1 and 2 represent the simulation design of the single E-shaped patch antennas with full ground and DGS. Figures 5, 6 represents the return loss, VSWR, 3D Gain and 2D radiation patterns at 16.07 GHz and 25.52 GHz. Table-2 elaborates the comparison between single patch antenna with and without DGS.
The simulated design of the suggested 2x2 array antenna with DGS on the ground is shown in Figures 3 and 4. The suggested 2x2 array antenna prototype is shown in Figures 8a and 8b. The proposed antenna's measured return loss and VSWR are shown in Figures 9 and 10. Figures 11 and 12 show a comparison of the manufactured antenna's simulated and measured return loss and VSWR. Figure 13 displays the 2D radiation patterns and 3D gain graphs for the suggested antenna. The findings demonstrated that the suggested 2x2 array antenna with DGS appears to have higher resonant frequencies with good return loss, better VSWR, high gain, and good bandwidth when compared to a single patch antenna. A 2x2 E-shaped patch antenna array with DGS comparison between simulated and experimental results is shown in Table 4.

.

, Claims:CLAIMS
We claim:
1) This invention is compact and having less manufacturing complexity E-shaped array antenna based on the DGS technique has been designed.
2) The results reveal that the designed array antenna with DGS performs well at multiband frequencies.
3) The proposed antenna resonates at multiple bands such as (12.28-14.52 GHz), (17.74-20.68 GHz), (20.96-23.34 GHz), (31.04 – 33.8 GHz) and (36.64 – 40 GHz) with good Return loss, Low VSWR and a Peak Gain of 7.4 dB. Besides, the suggested design is compact and eases of fabrication, making the antenna attractive for a wide range of Ku, k, and Ka-band applications.
4) The proposed 2x2 array antenna with DGS is suitable for satellite communications, space research, and radio navigation.

Pavada Santosh, Swetha Velicheti, Dr. P. Mallikarjuna Rao, Dr.M.Satya Anuradha Dated this 01st March 2023.