Design of substrate integrated waveguide sum-difference comparator

The model and software simulations of a novel substrate integrated waveguide (SIW) sum-difference comparator based on RdB-coupler with 90 degrees phase delay is proposed. Equivalent model parameters are initially used to determine geometric sizes and then numerical simulation is applied to make optimization and obtain electrical characteristic variations and electro-magnetic field distributions. An example comparator is presented for operating at 9GHz, together with S-parameters curves and field distributions. This comparator can be used in minimized direction-finding radar systems.