Abstract: A signal transmission apparatus includes a first waveguide, a second waveguide and a third waveguide. The transitions between the first, second and third waveguides are substantially co-impedance matched. The signal transmission apparatus may be a multi-port device, and may be used to transition high frequency signals from one component to another in a variety of applications.

Abstract: A signal transmission apparatus includes a first waveguide, a second waveguide and a third waveguide. The transitions between the first, second and third waveguides are substantially co-impedance matched. The signal transmission apparatus may be a multi-port device, and may be used to transition high frequency signals from one component to another in a variety of applications.

Abstract: A method for testing a pulse Doppler radar sensor circuit comprising at least one antenna, and a switch circuit, comprising the steps of 1) configuring said switch circuit such that a first path between an input terminal and a first output terminal and a second path between an input terminal and a second output terminal introduce different phase delays to an input signal, 2) providing an input signal to the switch circuit at said input terminal, and 3) comparing a signal at the first output terminal and a signal at the second output terminal to determine if the sensor circuit is functioning.