K-band Planar and Low-profile Fabry-Perot Cavity Antenna with a Coupled Strip-Slitline Feed Structure

摘要

In this paper, a design of a planar, low-profile, and high gain Fabry-Perot cavity antenna for K-band applications is presented. The antenna is consisted of a frequency selective surface (FSS) made of a circular hole array and a feeding structure made of a coupled strip-slitline. The FSS and the slitline both are lithographically patterned on a high permittivity substrate while the stripline is printed on top of a thin and low permittivity substrate. These two substrates are then closely appressed each other to form a planar structure. The measured results show that the proposed antenna has an impedance bandwidth of about 4% (vertical bar S11 vertical bar <=-10 dB), a maximum gain of about 10.4 dBi, and a 3-dB gain bandwidth of approximately 2.9% at the resonance frequency of around 20.8 GHz. The antenna's compact, planar, and lightweight profile, i.e., approximately 4 lambda(o) x 4 lambda(o) x 0.24 lambda(o) of a free-space wavelength at 21.0 GHz makes it promising for a small and efficient source in K-band applications.