60-GHz LTCC antenna array with microstrip to CPW transition

We present an antenna array design at 60 GHz on low-temperature co-fired ceramic (LTCC) with a microstrip to coplanar waveguide (CPW) transition. The design consists of aperture-coupled microstrip patch antennas on LTCC Heraeus HL2000 with small embedded air holes to synthesize a lower dielectric substrate. The arrays are excited through a microstrip-line feed network with quarter-wave matching via a microstrip to CPW transition. The transition is designed so that the antenna can be measured with the patch facing upwards while reducing the effect of the probe station. An open cavity is made to ensure the microstrip-line is also placed away from the probe station plate. Good agreement between simulated and measured return loss with simulated gain of 14dB is achieved.