Design of a DC-to-90-GHz resistive load

A resistive load with greater than 30 dB return loss for a frequency band of DC to 90 GHz is presented. Frequency dependence of the load impedance is removed by cancellation of the imaginary components of the impedance. Optimization of the load is achieved using commercial EM-based optimizers. Measurements, using a modified multiline TRL calibration, show an excellent match with EM simulations.