HF-VHF-UHF IQ Mixer With a Single SPDT Switch
2015 IEEE MTT-S International Microwave Symposium
An IQ mixer topology using passive components and a single SPDT switch is described with simulations and measurements at 7 MHz and 144 MHz. A test fixture permits experiments with a variety of switch candidates. Results are presented for MOSFET switches and an SPDT switch using a hybrid coil and ring of Schottky diodes. SSB conversion loss is near 6 dB. Measured IIP3 is +16 dBm for a MOSFET switch and +6 dBm for the diodes. The Schottky version exhibits much better 2nd order performance and stability of amplitude and phase differences between I and Q ports. Results at VHF using surface mount components suggest that the Schottky diode/hybrid coil switch is a promising candidate for low power near-zero IF applications.
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R. Campbell, "HF-VHF-UHF IQ mixer with a single SPDT switch," 2015 IEEE MTT-S International Microwave Symposium, Phoenix, AZ, 2015, pp. 1-4.