A 15-27 GHz Low Conversion Loss and High Isolation Resistive Ring Mixer for Direct Conversion Receiver

In this paper, a passive resistive ring mixer is demonstrated in a commercial 65-nm process. This mixer achieves a low conversion loss with a low Local Oscillator (LO) power and a high isolation between LO and RF ports. The gate terminals of core devices are biased at subthreshold voltage to improve the conversion loss. The mixer offers a conversion loss of 2.2-5.2 dB over 15-27 GHz when the LO power is 2.7 dBm. Meanwhile, a symmetrical layout helps to achieve the high LO-to-RF isolation which is larger than 47 dB in whole operating frequency range. When RF signal is at 24.01 GHz and IF signal is at 10 MHz, the measured input 1dB compression (IP
₁
dB) is up to 3 dBm. Owe to the structure of the passive mixer, zero dc consumption is achieved. The double sideband (DSB) noise figure (NF) is 4.7 dB at IF frequency of 10 MHz.