Abstract: A novel mixer of good noise performance for operation at microwave frequencies (e.g. the 22 GHz communications band) is disclosed. The mixer comprises a waveguide to which signals and local oscillations are coupled, and from which the intermediate frequency output is derived. The principal circuitry is provided on a metallized substrate set within the waveguide in a "finline" construction. The metallized substrate performs the essential functions of impedance matching the mixer to the source of signal and local oscillations, a bridge for isolating the signal port from local oscillations and for isolating the LO port from the signal, and means to adjust the application of signal and load to the mixer diodes for optimum signal conversion. The noise figure achieved is approximately 4 db at 22 GHz, and represents an improvement over known competitive designs.

Abstract: A single balanced planar mixer is disclosed suitable for use in the reception of electromagnetic waves of extremely high frequencies including millimeter waves. The mixer may be combined with an antenna, the combination being particularly suitable for use in antenna arrays. The arrangement is planar combining coplanar strip, coplanar line, and microstrip transmission lines formed on an insulating substrate in a single balanced arrangement providing isolation between the antenna port on the one hand and the local oscillator and IF ports on the other hand. Additional filters suitable for fabrication on a substrate are employed to provide isolation between the local oscillator and intermediate frequency ports. At lower frequencies, the arrangement may be in a hybrid format using an insulating substrate and discrete diodes. At higher frequencies the arrangement may be monolithically integrated using a gallium arsenide substrate with integrated diodes.