230 - 330 GHz Microstrip Leaky-Wave Antenna Array using BiCMOS BEOL Silicon Interposer

This paper presents a 2x1 microstrip leaky-wave antenna (LWA) array implemented using BiCMOS backend-of-line silicon-interposer technology. Each LWA consists of a 50 Ω microstrip loaded with 16 periodic leaky-wave unit cells, terminated with a radial-stub open circuit to provide broadband impedance matching. The array feeding network comprises a quarter-wave matched microstrip T-junction and a via-less grounded coplanar waveguide (GCPW)–microstrip transition. The two LWAs are separated by a small gap of 0.7 mm, making the array suitable for integration with monolithic microwave integrated circuits (MMICs). A prototype of the LWA array is characterized using a probe-based measurement setup. Its reflection coefficient, peak antenna gain, beam-steering range, and far-field radiation patterns are measured over the 230–330 GHz range and compared with simulation results.