Quasi-optics offers an attractive means of creating moderate-power solid-state millimeterwave transmitters. This paper presents the development of a 28 GHz oscillator, including an InP power HEMT and integrated with a planar, endfire antenna, which is used in testing metal reflectors designed for generating omni-directional patterns for point-tomultipoint distribution. Results of this work give insight into tailoring the reflectors for omni-directional active arrays.