Wideband and Circularly Polarized Variations of Sectoral Microstrip Antennas

Abstract

AbstractSectoral microstrip antenna is a variation of circular microstrip antenna and in the literature, various configurations of the same offering wideband, multi-band, and circular polarized response are reported. However, in many of those configurations, which are supposed to be functional at higher-order modes of the patch, the detailed explanation for the resonant modes present in the patch to achieve reported frequency characteristics is not discussed. This paper proposes a detailed study for the two of such Sectoral microstrip antenna designs. In the first design, stub-loaded variation of 2700 Sectoral microstrip antenna is presented whereas in the second variation, shorted and slot cut variation of 3300 Sectoral microstrip antenna is discussed. Using thinner substrate, in the stub loaded variation, wideband response due to the tuning of TM20 and TM02 modes is achieved thereby giving impedance bandwidth of 60 MHz (4.18%). In the shorted and slot cut design, circular polarized response due to the tuning in between TM1/2,0 and TM1/2,1 modes, thereby giving an axial ratio bandwidth of 11 MHz (1.8%) is achieved. The proposed designs are compact and low-profile ones since they are realized on a thinner and lossy substrate. The equivalents of the proposed Sectoral variations can find applications in WiFi and personal communication applications within a short distance range.KeywordsSectoral microstrip antennaWideband microstrip antennaCompact microstrip antennaCircular PolarizationRectangular stubShorting postRectangular Slot