A 1.8 GHz temperature drift compensated LC-VCO for RFID transceiver

A novel temperature-compensated LC-VCO is presented for RFID applications. By employing a low pass passive filter and an auxiliary varactor loop, the frequency drift is reduced by 70% without using any other active device. The effectiveness of the technique is demonstrated on a frequency synthesizer of a RFID transceiver. The frequency synthesizer is fabricated on a 0.18 μm RF process with a single supply of 1.8 V. The empirical measurements show that the VCO achieves a current consumption of 6 mA, while the passive temperature-compensated circuit does not increase the power consumption. The VCO has a tuning range of 1.6–2.1 GHz and phase a noise of − 124 dBc/Hz at 1 MHz offset from the 1.824 GHz carrier.