A 0.6-V 0.33-mW 5.5-GHz Receiver Front-End Using Resonator Coupling Technique

In this study, a low-power and low-voltage 5.5-GHz receiver front-end circuit is designed using a resonator coupling technique. An on-chip transformer combined with the parasitic capacitances from a low-noise amplifier (LNA), a mixer, and the transformer itself comprises two coupled resonators of the resonator coupling network (RCN). The RCN functions as a balun, and couples energy from the LNA to the mixer. Under the critical coupling condition, the RCN gives a maximal current gain at resonance frequencies, equivalent to the same level by an ideal transformer. The analysis shows that the current gain is quite tolerable to the coupling coefficient variation, an advantageous feature for on-chip transformer design. The technique is verified by the receiver front-end in 0.18-μm CMOS technology. The RCN possess a current gain as high as 12 dB at 5.5 GHz. The measured input return loss, conversion gain, and third-order intermodulation intercept point of the entire circuit are 16 dB, 17.4 dB, and -1.5 dBm, respectively. The noise figure is 7.8 dB at the IF frequency of 1 MHz. The power consumption is only 0.33 mW from a 0.6-V supply. The required local oscillator power is only -9.5 dBm. This receiver front-end successfully demonstrates the resonator coupling technique.