Circularly polarized U-Slot antenna

Circularly polarized single-layer U-slot microstrip patch antenna has been proposed. The suggested asymmetrical U-slot can generate the two orthogonal modes for circular polarization without chamfering any corner of the probe-fed square patch microstrip antenna. A parametric study has been carried out to investigate the effects caused by different arm lengths of the U-slot. The thickness of the foam substrate is about 8.5% of the wavelength at the operating frequency. The 3 dB axial ratio bandwidth of the antenna is 4%. Both experimental and theoretical results of the antenna have been presented and discussed

A compact rectenna using split ring resonator for energy harvesting

In this paper, a rectifying antenna circuit based on the concept of electrically small resonator is reported. To verify the concept, it is designed, simulated, and also tested to harvest electromagnetic energy at 3.1 GHz. It is observed through measurements that the proposed circuit is able to transfer 18% of the RF incident power into DC power. The DC output power and RF-to-DC efficiency are investigated with respect to frequency, and also the angular position of the rectenna system

Stacked S-band Slotted Waveguide Array Antenna with very low sidelobes

A very low 3D sidelobe (< -21 dB) S-band (2.4 GHz) Slotted Waveguide Array Antenna (SWGAA) design is presented in this paper. A single waveguide SWGAA have a fan beam radiation pattern in the elevation plane. The elevation beamwidth of the SWGAA antenna can be narrowed by stacking identically designed SWGAA elements. The stacking method, simulated results and anechoic chamber measurements are presented in this paper

Slotted Waveguide Array Antenna performance enhancement by parasitic elements augmentation

A novel design of Slotted Waveguide Array Antenna (SWGAA), at 8.5 GHz with beamwidth of 11° and > -21 dB sidelobe level, with each slot is augmented with a pair of inverted L-shaped parasitic dipoles is presented in this work. Each dipole is located beside the long edges of the slot. The slot cut from a rectangular waveguide acts as a magnetic dipole while the parasitic dipoles act as electric dipoles. Both dipole types act as radiating elements. If both are designed to radiate at the same frequency at the proper amplitude and phase, the radiation performance can be enhanced. Performance comparisons between conventional SWGAA design and the proposed design are presented in this work

A Millimeter-wave Aperture-coupled Simple Low-Profile Magneto-Electric Antenna

A millimeter-wave low-profile magneto-electric(ME) dipole antenna is presented in this paper. The proposed ME dipole antenna is designed on two pieces of substrate with different materials and fed by aperture-coupled technique. Unlike the previously reported ME dipole antennas, there is no vertical-cavity serving as a magnetic dipole in this design, while the magnetic dipole is formed by the gap between the two horizontal patches, this design makes the geometry of the ME dipole antenna simple and easy to be fabricated. Simulated results show that the proposed ME dipole has impedance bandwidth (VSWR ≤ 2) of 29.1% from 23.5 GHz - 31.5 GHz and a stable high gain of 8.3 ± 0.7 dBi across the operating frequency band

Surface Wave Antenna Metallic Cell Pattern Design Using Neural Network Method

This work presents a surface wave antenna metallic cell pattern prediction method which can be generated based on the required far-field radiation pattern by the mean of applying Wasserstein generative adversarial network (WGAN) and bi-directional gated recurrent unit (Bi-GRU) neural network models. The predicted metallic cell pattern has been 3D-modelled in CST and the radiation pattern shows less than 1 dBi variation level from the desired input radiation pattern

Circularly Polarized Magneto-Electric Dipole with Axial Ratio Enhancement

In this paper, we propose a new circularly polarized circular magneto-electric dipole antenna. The proposed antenna has a wide impedance bandwidth of 66.66% from 3.0 to 5.4 GHz, high stable gain with maximum gain of 9.3 dBi at 4.0 GHz and wide 3-dB axial ratio bandwidth of 44% from 3.5 to 5.35 GHz. The radiating element is smaller in size by 35% while maintaining a high stable gain, and wide 3-dB axial ratio bandwidth. To improve the 3-dB axial ratio, we introduced a pair of rectangular slots on the electric dipoles that can adjust the four ME-dipole modes for reducing the size of ground reflector. The antenna is designed on a RT/duroid® 5880LZ filled PTFE substrate with thickness of 1.27 mm and ϵr =2, tanδ = 0.0027

Cosecant-Squared Radiation Pattern Surface Wave Antenna for Millimeter-wave FMCW Vertical-Looking Radar System

This work presents our preliminary work on an electric field (E-field) prediction technique and near-field tofar-field transformation of a surface wave antenna with a cosecant-squared pattern for a millimeter-wave FMCW vertical-looking radar system. Fourier and Gaussian fitting models were used to predict the magnitude and phase of E-field on the antenna surface, and the prediction error at the center operating frequency of 34.5 GHz are 4.6% and 4.6° respectively. The far-field E-plane pattern was achieved by applying Fourier Transform to the predicted near-field E-field distribution

Metallic Pattern Prediction for Surface Wave Antennas Using Bidirectional Gated Recurrent Unit Neural Network

This work presents a surface wave antenna metallic pattern prediction from electric field in near-field by applying Bidirectional Gated Recurrent Unit neural network prediction model. The metallic pattern of the proposed antenna has been predicted by using Bi-GRU neural network model with prediction accuracy 100% at 34.5GHz. Different uniform mark-space-ratios (MSR) of the metallic pattern do not affect the metallic pattern prediction accuracy

Low cost 3D-printed monopole fluid antenna

Low cost 3D printed monopole fluid antenna is investigated. The PDMS container of the seawater is fabricated by 3D printing technology for reducing cost and complexity. The design parameters of the antenna have been studied for efficiency improvement. The achieved peak efficiency is about 70% at 2.75 GHz, and the impedance bandwidth is about 67%. Stable radiation patterns are demonstrated across the operating bandwidth. The radiation mechanism of the antenna has been explained