Millimeter Wave Photonic Tightly Coupled Array

Abstract

We present a tightly coupled array antenna excited by high-power photodiodes for millimeter wave transmit operation. The design includes thinned photodiode substrates for improved bandwidth performance at high frequency combined with the inherently lightweight, low-loss, and direct feeding architecture afforded by the photonic approach. Circuit and full wave simulations are conducted for array design and compared against the traditional electronic arrays in the literature. A prototype 1 \times 3 photonic array is developed and characterized to validate the design which achieves a 3 dB ( VSWR < 1.4 ) radiated power bandwidth of 4.6:1 across 13-60 GHz and maintains a 3 dB bandwidth near 4:1 across scan angles up to 30°. The fabricated array exhibits a 3 dB radiated power bandwidth of 1.8:1 across 30-55 GHz and a maximum measured effective isotropic radiated power of 19.4 dBm at 40 GHz.