Dhaval Pujara

Improving the Cross-Polar Performance of an Offset Parabolic Reflector Antenna Using a Rectangular Matched Feed

This letter presents the improved cross-polar performance of a matched feed with an offset parabolic reflector antenna of low focal-length-to-diameter (F/D) ratio and higher offset angle. In the pyramidal horn, the higher order mode (TE11) has been added in correct amplitude and phase with respect to the dominant mode (TE01) . Parametric study on the secondary radiation pattern has been carried out for different values of offset angle. The numerical results have been presented on radiation pattern for both linearly polarized and circularly polarized rectangular matched feed. The design of a rectangular matched feed and its simulated secondary patterns have also been included.

Cross-Polarization Cancellation in an Offset Parabolic Reflector Antenna Using a Corrugated Matched Feed

This letter presents the design of a dual-mode corrugated matched feed to cancel the unwanted high cross polarization and beam squinting in an offset parabolic reflector antenna. The matched feed concept has been implemented in a cylindrical corrugated structure by adding a higher order HE21 mode to the fundamental HE11 mode. The designed feed was then used to illuminate a linearly, as well as a circularly, polarized offset parabolic reflector antenna, and the secondary radiation patterns were computed. Significant improvement in the cross polarization was observed when the results were compared to that of a conventional corrugated horn illuminated offset reflector antenna.

Predicting the Performance of Pyramidal and Corrugated Horn Antennas Using ANFIS

This letter presents the development of an adaptive neuro fuzzy inference system (ANFIS)-based model for predicting the performance of a pyramidal and a conical corrugated horn antennas. Different ANFIS-based models were developed. Using these models, horn return-loss characteristics and radiation patterns (copolarization and cross-polarization) can be obtained with great accuracy for any combination of design parameters. The results obtained using ANFIS models were compared to that of the commercial horn antenna design software and found in close agreement. The advantage of the proposed method lies with the fact that, with less time and minimum computational resources, the return-loss and radiation characteristics of a horn antenna under test can be obtained with high degree of accuracy.

Performance comparison of a matched feed horn with a potter feed horn for an offset parabolic reflector

The present paper deals with the comparison of matched feed performance with that of the conventional potter horn when used with an offset parabolic reflector. The effect of TE21 mode amplitude on the cross polarization has been studied in order to ascertain the suitable TE21 modal amplitude. Followed this, the behavior of change of TE21 modal amplitude with offset angle (thetas0) has been investigated. The effect of cross-polarization variation as a function of (F/D) ratio has been studied for both the matched feed and the potter horn. Finally, the beam squinting phenomenon in case of circular polarization has been studied for the matched feed and the results were compared with that of the potter horn.

Cancellation of High Cross-polarization of an Offset Parabolic Reflector Antenna using a Rectangular Matched Feed

Abstract This paper presents the design and the experimental results of a dual-mode rectangular-matched feed. This type of feed cancels the unwanted high cross-polarization generated by the offset parabolic reflector antenna. In order to design this feed, higher order TE11 mode has been added in correct amplitude and phase with the fundamental TE01 mode in a rectangular structure. The proposed feed was then used as a primary feed to illuminate a linearly polarized offset parabolic reflector antenna. Through experimental results, it is verified that such a feed suppresses the undesired high cross-polarization introduced by the offset geometry of an offset reflector antenna. This kind of feed is very much suitable for monopulse tracking radar.

Historical and Planned Uses of Antenna Technology for Space-Borne Microwave Radiometers

This paper reviews the historical and future uses of antenna technology for space-borne microwave radiometers. The radiometer antennas are discussed, starting from the Dicke-type radiometer, as used in the Microwave Sounder Unit (MSU), to the present-day total-power radiometer. The antennas cater to the need for very high beam efficiencies, of the order of 95% to 98%. The paper also summarizes the specifications, design issues, and the performance of various radiometer antennas.

Analysis and synthesis of microstrip patch antenna using Artificial Neural Networks

In the present paper, the analysis and the synthesis models of rectangular, circular and equilateral triangular microstrip patch antennas using Artificial Neural Networks are presented. The analysis model takes antenna geometrical parameters as inputs and gives resonant frequency and return-loss as outputs. The synthesis model gives patch dimensions as output for a given set of antenna performance parameters.

Multilayer slotted microstrip antenna for Wi-Fi application

A simple microstrip antenna with multilayer structure having 20% bandwidth and spreading over 4.4/5.3-GHz Wi-Fi communication band is introduced. Due to the stacking of two substrates and slotted patches, a wide bandwidth is obtained as compared to simple rectangular patch. This antenna is compact with occupying an overall area of 26×30×6 mm3. It gives a moderate gain over a whole frequency band with good radiation characteristics. The entire design with simulation results are demonstrated and discussed.

Design and development of a wideband tree shaped fractal dielectric resonator antenna

Design of a wideband tree shaped fractal dielectric resonator antenna (DRA) is proposed in this paper. Trapezoidal shaped conformal strip feed is used as feeding mechanism. Implementation of fractal geometry on DRA has been utilized to reduce Q-factor and subsequently achieve wide bandwidth (BW). Tetrahedron shaped notches are created as fractal iterations to improve bandwidth. Impedance bandwidth of about 86.32%, with frequency range from 4 to 10.1 GHz is achieved. Average gain of about 6 dBi over the entire band of interest is achieved. Various design parameters, and corresponding results are discussed.

Analysis of an elliptical patch antenna using artificial neural networks

In the present paper, the analysis of a circularly polarized elliptical patch antenna using artificial neural networks is pesented. Radius of semi-major axis, feed location to the microstrip patch and the height of the dielectric substrate are taken as inputs to the neural network, while resonant frequency and return-loss are obtained as the outputs. The ANN generated results were found in close agreement with those of simulated results.