A Wideband Circularly Polarized Microstrip Patch Antenna With Embedded Shielding Package Based on Quarter-Mode Substrate Integrated Waveguide Feed

In this paper, the feasibility of using the half-mode/quarter-mode of a substrate integrated waveguide (HMSIW/QMSIW) cavity to feed microstrip patch antennas (MPAs) is explored; based on this, a circularly polarized (CP) MPA fed by the sequential rotation QMSIW cavities is proposed. For more compact and higher integration, the active circuits are packaged inside the microstrip patch antenna. Correspondingly, the QMSIW cavities have also been chamfered, and slots are designed on the upper surface to reduce the influence of the chamfer operation. The SIW cavities introduced an additional resonant mode, which can essentially enhance the bandwidth of the MPAs. The fabricated prototype shows a bandwidth of about 9% (1.42GHz - 1.55GHz) with an average CP gain of 7 dBic. In addition, the adoption of HMSIW/QMSIW cavity excitation allows the microstrip patch antenna to retain a seamless ground plane as well, which facilitates further integration with other components of the communication system by printed circuit board lamination technology.