Low Cross-polarization Performance Research Articles

An injection molded circularly polarized endfire multibeam antenna with wide axial ratio beamwidth coverage using rhombic waveguide element

This article presents a circularly polarized (CP) endfire multibeam antenna with wide axial ratio (AR) beamwidth coverage. It is based on a dielectric loaded waveguide structure and consists of a 4 × 4 Butler matrix and four rhombic waveguide elements. Regarding to each element, it decomposes the incoming linearly polarized waves into two orthogonal modes with equal amplitude and obtains 90° phase difference between the two modes via their different dispersion characteristics to realize CP radiation. Study found that the proposed element has low cross-polarization performance within a wide beamwidth, which contributes to realize wide 3-dB AR beamwidth coverage in the multibeam array. In fabrication process, injection modeling and electroplating techniques are employed to construct the proposed antenna. By using this way, the structure splitting and misalignment problems, which usually existed in conventional designs, can be avoided, and the antenna weight can be maintained to a moderate level. Through the experiment, it is found that the proposed antenna can achieve an overlapped 3-dB AR bandwidth of 10.7% from 9.7 to 10.8 GHz and a wide 3-dB AR beamwidth coverage of 91°.

3D Printed Corrugated Plate Antennas With High Aperture Efficiency and High Gain at X-Band and Ka-Band

A design criterion for a compact 3D printed high gain corrugated plate antenns that has high aperture efficiency and wide bandwidth is presented in this paper. The proposed design criterion is validated numerically and experimentally by fabricating 3D printed and Aluminium prototypes for X-band and Ka-band applications. The proposed antenna structure consists of two layers, where the electromagnetic energy (EM) is launched into a cavity that exists between both layers and the EM energy is coupled to the surface of the second layer. The second layer is the radiating structure which consists of three slots surrounded by a rectangular cavity and periodic corrugations that significantly improve the gain of the antennas. The 3D printed prototypes of the proposed antennas are fabricated and tested to validate the proposed design criterion, and their performance is compared to the Aluminium metallic counterparts. Using 3D printing technology, to fabricate the proposed antennas offer low cost and low weight alternatives to the Aluminium metallic prototypes. The measured results of the fabricated prototypes show high gain, high aperture efficiency, low side lobe level, and low cross polarization performance over a wide bandwidth.

A broadband and low cross polarization antenna with a balun of microstrip line coupling to slot line.

In this paper, a wide-band low cross polarization antenna with a structure of microstrip line coupling to slot line as the balun is proposed. The radiation part of the antenna is fed by two pairs of parallel transmission line via a transition from a slot line which is coupled by a microstrip line. Because it is fed by parallel transmission lines, which is balanced-fed structure, the antenna can achieve an improved low cross-polarization performance. The height of the antenna is 0.146λ0 (λ0 is the wavelength of lowest frequency). The prototype antenna demonstrates a measured impedance bandwidth of 93.5% (2.7–7.44 GHz), a 3-dB-gain bandwidth of 77% (2.7–6.1 GHz), and a maximum gain of 10.5 dBi at 4.5 GHz.

A CPW-fed broadband quasi-Yagi antenna with low cross-polarization performance

This paper presents a uniplanar quasi-Yagi antenna with the coplanar waveguide feed line. A novel driver dipole is proposed to expand the working frequency band of the antenna. Due to the unique driver dipole, the proposed quasi-Yagi antenna can work from 3.75 to 10.4GHz with good end-fire radiation gain (>4dBi) and low cross-polarization performances. To verify the design, a prototype antenna is fabricated and measured. The experimental results are in accordance with the simulation results very well.

The Planar Ultrawideband Modular Antenna (PUMA) Array

A fully planar ultrawideband phased array with wide scan and low cross-polarization performance is introduced. The array is based on Munk's implementation of the current sheet concept, but it employs a novel feeding scheme for the tightly coupled horizontal dipoles that enables simple PCB fabrication. This feeding eliminates the need for “cable organizers” and external baluns, and when combined with dual-offset dual-polarized lattice arrangements the array can be implemented in a modular, tile-based fashion. Simple physical explanations and circuit models are derived to explain the array's operation and guide the design process. The theory and insights are subsequently used to design an exemplary dual-polarized infinite array with 5:1 bandwidth and VSWR <; 2.1 at broadside, and cross-polarization ≈ -15 dB out to θ = 45° in the D- plane.