Half-Mode SIW Variable PIN Diode Attenuator

A half-mode substrate integrated waveguide (HMSIW) variable attenuator for operation in the 6 GHz to 10 GHz frequency range is presented. Different levels of attenuation are achieved by adjusting the level of the dc bias applied to four surface mounted PIN diodes. After fine adjustment of the PIN diode's equivalent circuit, the simulation and measured results are in good agreement, and the initial goal of up to 6 dB attenuation is achieved and verified by measurements of a prototype circuit.