Analysis of radiation patterns of rectangular microstrip antennas with uniform substrate

IEEE Open J. Antennas Propag.

2021

This paper presents a differentially fed dual-band hybrid antenna with broadside radiation, enhanced bandwidth, and high selectivity. The proposed antenna is constructed using a single-layer substrate based on rectangular patch resonator and substrate integrated waveguide (SIW) cavity. Herein, TM 10 and TM 12 modes of the rectangular patch resonator, together with TE 21 and TE 23 modes of the rectangular SIW cavity, are selected for resonances in the concerned dual-band radiation. Among them, TM 10 and TE 21 are employed for the lower passband, while TM 12 and TE 23 for the higher passband. Besides, for achieving broadside radiation performances in both bands, two arrays of shorting pins are loaded in the rectangular patch resonator and the constituted electric wall surround the rectangular SIW cavity is properly truncated to reshape the radiation patterns of TM 12 and TE 23 , respectively. Notably, the resonant and radiation properties of all the involved modes are obtained with theoretical deduction. Furthermore, the cascaded trisection composed of the SIW cavity, the patch resonator, and the radiation impedance creates two radiation nulls in each upper stopband of both passbands and the mixed coupling between two resonators generates another radiation null to be located in the lower stopband of the higher passband. For demonstration, a prototype antenna with the dual bands at 3.5 and 5.8 GHz is fabricated and tested. The measured results show that the antenna has achieved an improved bandwidth (|S dd11 | < −10 dB) from 3.26 to 3.58 GHz and 5.60 to 5.90 GHz, respectively, with stable broadside gains of around 8.5 dBi. In addition, in the stopband, three radiation nulls are created at 3.71, 5.32, and 6.12 GHz for effective enhancement of dual-band frequency selectivity.INDEX TERMS Bandwidth enhancement, dual-band antenna, high selectivity, radiation pattern reshaping, single-layer.

Section: ) Analysis Of Rectangular Patch Antennamentioning

confidence: 99%

A Low-Profile Dual-Band Filtering Hybrid Antenna With Broadside Radiation Based on Patch and SIW Resonators

IEEE Open J. Antennas Propag.

2021

“…Due to the fact that slot radiator can be considered as a magnetic dipole with reference to the Babinet's principle, its far-zone radiation patterns can be calculated by using the equivalent magnetic current distribution along the slot resonator. 36 The field of the λ-mode is assumed to be simplified in the form of 37 :…”

Section: Radiation Patterns Of the Conventional Slot Antennamentioning

confidence: 99%

A folded higher‐mode slot antenna with enhanced bandwidth and radiation pattern reshaping

Int J RF Microw Comput Aided Eng

2021

In this article, an approach to reshape the radiation pattern of the 1.5λ-mode of the slot antenna is proposed. Unlike previous works on slot antenna operating at the fundamental mode with a broadside radiation performance, the proposed slot antenna holds four symmetric radiation beams by resonating at its radiative λand 1.5λ-mode. Initially, by folding the straight slot radiator at one short-ended terminal, radiation patterns in H-plane of the 1.5λ-mode could be significantly reshaped from the broadside beam into four symmetric radiation beams, while that of the λ-mode almost remains unchanged. Then, a pair of slot stubs is symmetrically introduced to further improve the bandwidth of multibeam radiation performance. An antenna prototype is finally fabricated and measured to validate the predicted performance. Good agreement between the simulated and measured results is observed. The antenna operates in a frequency range of 3.64 to 3.96 GHz with S 11 lower than À 10 dB under dualmode resonance. And four symmetric beams for radiation have been successfully obtained at the directions of 40 , À 40 , 140, and À 140 with respect to the broadside direction across the whole operating bandwidth.

“…At the very beginning, our main target is focused on the physical insight into the working mechanism about E-plane HPBW enhancement of the MPA. Based on the classical cavity model [1,25], the far-zone radiated fields of the conventional MPA in the Eplane can be calculated by using two equivalent slots at the edges of the radiating patch. Therefore, when H is much smaller than λ 0 , the radiation pattern of the antenna operating in the fundamental mode could be expressed as…”

Section: E-plane Half-power Beamwidth Extensionmentioning

confidence: 99%

Low‐profile microstrip patch antenna with simultaneous enhanced bandwidth, beamwidth, and cross‐polarisation under dual resonance

IET Microwaves, Antennas & Propagation

Gao

et al. 2020

A low‐profile microstrip patch antenna (MPA) with wide bandwidth, wide beamwidth, and reduced cross‐polarisation is proposed here. Firstly, the far‐zone radiated fields of the MPA are deeply studied to improve its radiation performance. It demonstrates that the E‐plane half‐power beamwidth (HPBW) of the antenna could be progressively widened by using a single equivalent slot instead of two equivalent slots. Meanwhile, its high cross‐polarisation of the H‐plane radiation patterns could be successfully decreased down by enlarging the width of the rectangular patch and loading the shorting pins. Secondly, the input impedance of the MPA operating in the fundamental mode is extensively investigated. The results illustrate that the resonant frequencies of its dual modes could be reallocated in proximity to each other for bandwidth enhancement by properly selecting the dimension of radiating patches. Finally, the proposed antenna is fabricated and tested. Experimental results show that the antenna has gained an improved bandwidth (|S11|<–10 dB) of about 12% ranging from 2.70 to 3.03 GHz, while keeping a thin thickness of about 0.029 free‐space wavelength. Besides, its H‐plane cross‐polarisation is kept below −20 dB. Most importantly, the E‐plane HPBW of the antenna is extended to around 140° over the wide band.