A Millimeterwave High-Speed SPDT-Pin-Switch with Perfectly Decoupled Ports

For polarization switching, a high-speed single-pole, double-throw PIN-switch has been developed featuring some remarkable characteristics. The switch is materialized as a window in the cross-section plane of a WR-1O waveguide. A center frequency of 94 GHz was chosen. The basic problem of bandwidth limitation has been overcome by using low dielectric constant substrate material. Together with an appropriate layout of the window, undesired capacitances have been minimized yielding very high switching speeds. Moreover, no tuning or compensating elements are required being spaced from the diode window along the waveguide. Decoupling of the two output ports and the input is achieved by using a new waveguide ring-junction which guides energy being reflected from the short-circuited port of the switch to the open one instead of back to the input.