Stripline microwave balanced mixer circuit

Claim 1

A microwave balanced or push-pull mixer circuit for an operating frequency formed in stripline technology having first and second input terminals and an intermediate frequency signal terminal each having an impedance Z 0 comprising, a differential transformer which for applying two input voltages to be mixed through said first and second input terminals with said first one connected through two quarter wave length striplines to first and second transformer output terminals and said second input terminal connected to said second transformer output terminal through the inner conductor of an arcuate-shaped coaxial line, an arcuate-shaped stripline connected to the second transformer output terminal and with one end connected by a through-contact to a ground plate, and the other outer end connected to the first transformer output terminal, first and second semi-conductor diodes connected together with a common terminal, with said first one mounted between the first transformer output terminal and an intermediate frequency signal output terminal and said second diode mounted between the second transformer output terminal and the intermediate frequency signal output terminal and poled differently than said first diode relative to the intermediate frequency signal output, means for blocking the frequency range of the two input voltages connected ahead of said diodes and for matching to the impedance Z 0 , two symmetrical striplines (17, 18) connected between said first and second transformer output terminals (4, 5) and the non-common terminals (19, 20) of said first and second diodes , and said striplines being enlarged near the noncommon terminals so that parallel capacitances are formed in the area of said diode terminals (19, 20), and the arcuate-shaped coaxial line (10) and the stripline (7) extending symmetrically relative thereto and which extend from said first and second differential transformer output terminals (4, 5) are designed to be shorter than a quarter wave length at the operating frequency so that parallel inductances are formed, and tuned such that the impedances of said first and second diodes at the differential transformer output terminals (4, 5) are respectively transformed to the impedance Z 0 , the width of said two quarter wave length striplines (11, 12) is selected such that they have an impedance of Z 0 .√2, another stripline (14) mounted between said inner conductor (13) of the coaxial line (10) on the end away from the differential transformer output terminals (4, 5) and the second input terminal (1), so that the overall length of the coaxial line (10) and of said another strip-line (14) equals a quarter wave length and the impedance of these two lines is equal to Z 0 .√2, and blocking the frequency range of the two input signals, a blocking circuit composed of a stripline coil (26) mounted between said common diode terminal (23) adjacent the intermediate frequency signal output terminal (3), said blocking circuit selected such that, at the desired intermediate frequency, the impedance Z 0 occurs at the intermediate frequency signal output terminal (3).