Planar push=pull signal mixer - has earthing surface of microstrip line forming overlapping regions with slit of skid-fin line of opposite substrate side

摘要

The oscillator signal is supplied via a microstrip line and the h.f. signal via a slit, or skid-fin line to two mixing diodes. The i.f. signal is coupled via a shunt circuit from the microstrip line. The latter and the slit line lie at the same substrate side and contact the mixing diodes via their conducting surfaces. The earthing surface of the microstrip line forms overlapping sections with the conductive surfaces of the slit line on the opposite side of the substrate. The overlapping sections are so arranged and dimensioned that the impedance for the oscillator frequency in direct vicinity of the diode contacts of the slit line side is negligible between the conductive surfaces and a earthing surface. The latter for the microstrip line has a slotted recess of quarter wave length for the oscillator frequency, starting at the end of the slit line and extending in the direction of the microstrip line.