Directivity Enhancement of a Circular Microstrip Antenna with Shorting Post

Cavity Field Modulation With Modulating Circular Patch Antenna Surface: A Key to Realize Reduced Horizontal Radiation and Omni-Present Improvement in Radiation Performance

“…Considering patch of radius a=7 mm, pin diameter d=1.2 mm, substrate thickness h=0.787 mm and new effective dielectric constant of (ε r ) N =1.7 (equation 9), patch plate area A p =190 mm (equations 6 and 7); the calculated f r for Antenna#3 is 9.3 GHz which is very close to that obtained in equation (10). The simulated and measured resonant frequency of same antenna (10.01 GHz and 10.02 GHz respectively) is documented in results section (Section IV, Fig.…”

“…The technique such as slot-loading with aperture coupling [7] and the use of 3 stacked ground plane with slot and shorting vias [8] have been adopted to achieve around 7.8 dBi gain with no improvement in PP (Copolar to cross-polar radiation isolation). To further increase the gain from 7.2 dBi to 9 dBi with PP of 18-19 dB only, the annular ring antenna in [9] was loaded with shorting vias (with branch line couplers), while numerous shorting vias beneath the circular patch have been reported in [10]. Notably, a structure similar to [8]- [10] has been reported in [11], and it can achieve high gain of 11 dBi but suffers from poor polarization purity of 17 dB and a much-distorted radiation pattern with a high side-lobe level.…”

“…To further increase the gain from 7.2 dBi to 9 dBi with PP of 18-19 dB only, the annular ring antenna in [9] was loaded with shorting vias (with branch line couplers), while numerous shorting vias beneath the circular patch have been reported in [10]. Notably, a structure similar to [8]- [10] has been reported in [11], and it can achieve high gain of 11 dBi but suffers from poor polarization purity of 17 dB and a much-distorted radiation pattern with a high side-lobe level. To attain high gain of around 6.8 dBi to 8 dBi for patch antenna, various techniques have been investigated, such as the adaptation of circular dual-stacked dense dielectric patch [12], replacement of circular patch geometry by hexa-decagon circular patch [13], and the use of graphene-based patch [14].…”