Design of Filtering-Radiating Patch Antennas with Tunable Radiation Nulls for High Selectivity

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Original languageEnglish
Pages (from-to)2125-2130
Journal / PublicationIEEE Transactions on Antennas and Propagation
Issue number4
Online published9 Feb 2018
Publication statusPublished - Apr 2018


This communication demonstrates a method to design filtering antennas by using the filtering-radiating patch (FRP). The so-called FRP is a structure of a rectangular patch etched with slots. It inherits the radiation performance of conventional patch antennas, and more importantly, introduces filtering feature with a radiation null at either the upper or lower band edge of radiation efficiency curve. The frequencies of radiation nulls are easy to control. Based on the FRP, a novel filtering antenna is proposed. Two radiation nulls are realized at both band edges of the antenna efficiency curve, leading to a sharp band skirt and good selectivity in the boresight gain response. The locations of the two radiation nulls can be flexibly controlled by the lengths of slots. A prototype is fabricated and tested. The measured results show an impedance matching bandwidth of 7% with a center frequency of 5.24 GHz, two radiation nulls at 4.7 and 5.85 GHz, respectively, a realized gain of 6.6 dBi, the cross-polarization rejection larger than 23.4 dB, and the front-to-back ratio better than 15 dB. The presented method demonstrates the capability of not only achieving good filtering-radiating performances but also possessing very simple structures by only etching slots on the patch of a conventional microstrip antenna.

Research Area(s)

  • Antenna, filtering antenna, filtering-radiating patch (FRP), patch antenna, realized gain