Broadband micromachined J-band directional couplers

Advances in the MMIC technology have enabled development of millimeter-wave (MMW) to terahertz radar and communication systems [1-3]. The short wavelength at these frequency bands enables the integration of antennas and other passive components with MMIC transceiver modules to develop fully integrated communication links and radar front-ends. Directional couplers are essential components in the design of radar systems. They are typically used to divide local oscillator (LO) signal between the transmit and receive stages in order to maintain coherence in the system [1]. Waveguide directional couplers are of interest for sub-MMW and terahertz applications due to their low loss and simplicity of integration with other micromachined components.