| dc.description.abstract | This paper investigates RF receiver front-end circuits for Medical Implant Communication Service (MICS). A 0.18 μm TSMC CMOS technology was adopted to implement the following circuits, gm-boosting low noise amplifier, low power consumption low noise amplifier, input impedance match mixer, low power consumption mixer, receiver circuit (LNA + Mixer), and voltage controlled oscillator.
The first section is the design of two low noise amplifiers; An inverse gain between transistor’s gate and source was used to amplify the transconductance gm. Thus, this gm-boosting technique was used in LNA by adding cross couple capacitors. The measured gain is 11.84 dB with input and output return losses lower than 10 dB. The obtained noise figure and P1dB are 4.11 dB and -26dBm, respectively. The power dissipation of the circuit core is only 1.74 mW. In another LNA, the current reuse technique was applied for low power consumption. The shunt-feedback amplifier (SFB) and common-gate amplifier (CG) were combined to obtain a high gm. The measured gain is 10.37 dB with input and output return losses lower than 10 dB. The obtained noise figure and P1dB are 4.77 dB and -25 dBm, respectively. The power dissipation of the circuit core is only 0.51 mW.
The second section describes the design of two mixers and a receiver. The size of transistors and resistors are optimized for the input impedance match without using huge area inductor. The measured conversion gain is 5.57 dB at 403.5 MHz. And the obtained P1dB and IIP3 are -11.5 dBm, and 3 dBm, respectively. The achieved isolations of LO_RF, LO_IF are better than -30 dB, and the RF_IF isolation is lower than -39 dB. The power dissipation of the circuit core is 2.88 mW. In another mixer, the local power is amplified to obtain the higher conversion gain. The current reuse technique was used to lower the power consumption. The measured conversion gain is 10.2 dB at 403.5 MHz. The obtained P1dB and IIP3 are -11.5 dBm, and 3 dBm, respectively. The achieved isolations of LO_RF, LO_IF are lower than -48 dB, and the RF_IF isolation is lower than -47 dB. The power dissipation of the circuit core is only 0.98 mW. Finally, LNA and mixer were combined to be a receiver. The measured conversion gain is 19.74 dB at 403.5 MHz. The noise figure is 7.02 dB with the input/output return losses of 7.9 dB and 24.5 dB. The obtained P1dB and IIP3 are -24 dBm, and -13 dBm, respectively. The achieved LO_RF, LO_IF isolations are lower than -72 dB, and the isolation RF_IF is lower than -28 dB. The power dissipation of the circuit core is only 1.65 mW.
The third section describes the design of a voltage controlled oscillator. The transformer feedback was adopted to achieve low supply voltage. From the measurement the oscillation frequency of the designed VCO is 393.5 MHz with a phase noise of -137.37 dBc/Hz at 1 MHz offset. The output power of VCO with cable loss is -5.66 ~ -4.76 dBm. The power consumption of VCO is 1.23 mW with an excellent Figure-of-Merit (FOM) of -188.33 dBc/Hz. | en_US |