Low-profile endfire radiating wideband antenna for Ka band applications

This paper analyzes the performance characteristics of a coupled microstrip resonator antenna when scaled to operate in the Ka band. The antenna is low-profile, vertically polarized, radiates in the endfire direction, and is mountable on large metallic surfaces. It is comprised of a coaxial fed trapezoidal launcher along with six rows of coupled microstrip resonators. The base antenna design is modeled, simulated, fabricated, and measured. Validation of the accuracy of this model is achieved through good agreement between the measured and simulated results. The antenna model is then scaled, simulated, and compared against the performance of the base model. A bandwidth of 5.5–10.8GHz for VSWR < 2 is achieved with a realized peak gain of greater than 8.5dBi over the operating range for the base design. When scaled, a bandwidth of 20.9–40.8GHz for VSWR < 2 is achieved with a realized peak gain greater than 5.3dBi over the operating range. Both designs achieve a profile of less than 0.087λ0 (where λ0 is the center frequency wavelength in free space) and a radiation efficiency greater than 97%.