Frequency-agile patch element using varactor loaded patterned ground plane

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

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Original languageEnglish
Article number5685281
Pages (from-to)619-626
Journal / PublicationIEEE Transactions on Microwave Theory and Techniques
Issue number3
Publication statusPublished - Mar 2011


This paper presents, for the first time, a method to realize the concept of frequency agility on patch-type circuits, which have found more applications at very high frequencies because of its simple structure. A patterned ground plane has recently been proposed for size reduction of patch-type circuits making them more favorable at lower frequencies. An additional auxiliary patch on the ground plane is proposed in this paper as a mechanism to change the capacitance between the upper patch and ground plane. The patterned ground plane loaded with tunable capacitors is applied to the patch element to realize frequency agility. For demonstration, a frequency-agile rectangular patch hybrid coupler with a varactor loaded patterned ground plane is designed to operate over a frequency range of 50% (from 1.5 to 2.5 GHz) with good return loss, small amplitude imbalance, and quadrature phase characteristics. © 2006 IEEE.

Research Area(s)

  • Frequency agile, patch-type circuit, patterned ground-plane structure