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Hybrid Microstrip Mixer and Circuits Constructed Therefrom

IP.com Disclosure Number: IPCOM000082257D
Original Publication Date: 1974-Nov-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Clouser, PL: AUTHOR

Abstract

This hybrid microstrip mixer provides good spurious signal rejection and/or conversion loss improvement because of image enhancement.

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Hybrid Microstrip Mixer and Circuits Constructed Therefrom

This hybrid microstrip mixer provides good spurious signal rejection and/or conversion loss improvement because of image enhancement.

The basic circuit of Fig. 1 includes a single-ended input mixer 1 that includes a voltage doubler 2 and a 180 degrees intermediate frequency (IF) hybrid 3. The output of doubler 2 is coupled to the input of centertapped transformer 4 of hybrid
3. The radio frequency (RF) and local oscillator (LO) input signals are applied to the common input of doubler 2 and past choke 5 to junction 6, which connects mixing diodes 7, 8. The mixed signals passed by doubler 2 are applied to the transformer 4. Capacitors 9 provide ground isolation and capacitors 10 provide an RF/LO bypass.

An appropriate bias supply, not shown, is connected across the bias terminals 11. The circuit provides common-mode rejection to spurious signals through the combination of the transformer 4 and diodes 7, 8. Circuit 2 is analogous to a known voltage doubler power supply. When operated backwards, the circuit of Fig. 1 becomes a harmonic generator with common- mode (even-harmonic) rejection. The microstrip substrates 2a, 3a, cf. circuits 2, 3, are shown schematically in Fig. 1.

In the circuit 15 of Fig. 2, a 90 degrees RF/:LO hybrid 20 provides separate inputs for the local oscillator and received microwave signals LO and RF, respectively. The outputs of hybrid 20 are connected to the respective inputs of a pai...