I. INTRODUCTION
Microstrip antennas have been widely used in array
applications due to their planar structure, ease of integration
and low-cost [1], [2]. This makes them a good candidate to be
integrated with Si chips for the purpose of spatial power
combining. In this study the differential output from the chips
led to the design of a differential microstrip antenna. In
addition to that an extensive design study including full-wave
simulations had to be done to account for the packaging effects.