Low-loss millimeter -wave power divider based on a synthesized insulated image guide

Based on a synthesized version of insulated image guide operating in E_x¹¹ mode (where the electric field is primarily parallel to the ground-plane), a low-loss 1:3 power divider is designed and measured. This waveguide is shown to have low transmission loss as well as low radiation loss at bends and dividing junctions. Net insertion loss of about 2.3 dB (or about 10 dB including the loss of the 1:3 division, 4.8 dB, and the loss of planar excitation circuits comprising CPW probe pads and micro-strip baluns) together with excellent phase balance of less than ±9° was measured between 85 GHz and 95 GHz. In addition, a matched load to the image guide mode is presented, based on a field-coupled planar dipole circuit.