A Compact Microstrip-Fed Planar Dual-Dipole Antenna for Broadband Applications

We present a broadband endfire planar circuit antenna that is suitable for applications in microwave, millimeter (mm), and submillimeter (sub-mm) wavelengths. We have cascaded two dipoles of different lengths in series to broaden the bandwidth. Two printed directors and a truncated ground plane are used to achieve high front-to-back (F/B) gain ratio. The parallel stripline feeding the antenna's drivers is connected directly to microstrip without an intermediate stage. This simple antenna design is easily integrated into microstrip circuits. In this letter, we focus on the design of a Ku-band antenna with 7 GHz bandwidth and F/B gain ratio of ~ 18 dB. Design and analysis of the antenna were performed using rigorous electromagnetic simulations, and we experimentally validated the performance of the antenna by measuring the beam patterns and return loss of an antenna fabricated on a Roger RO 4350 printed circuit board. Finally, we present two unique example applications of the antenna in the sub-mm detectors area.