A 3–10-GHz 13-pJ/Pulse Dual BPSK/QPSK Pulse Modulator Based on Harmonic Injection Locking

A method is presented to phase-modulate RF pulses through an injection-locking technique. The modulator can produce either binary phase-shift keying or quadrature phase-shift keying modulated wave packets (pulses). The RF pulses are produced using a fast on/off switching technique to power up and power down a tunable ring oscillator whose free-running frequency can be tuned from 3 to 10 GHz. Experiments show that the modulator´s minimum energy consumption is 13 pJ/pulse for a carrier frequency of 3 GHz, while its maximum consumption is 18 pJ/pulse when the carrier frequency is 10 GHz. The energy consumption figures are for 2-ns-long pulses with amplitudes of 300 mV at 3 GHz and 200 mV at 10 GHz. The pulse repetition rate is 250 MHz. The measured root-mean-square jitter of the oscillator, integrated from 100 Hz to 1 MHz, is below 3.6 ps. The chip was fabricated in 130-nm CMOS and it occupies a total area of 0.85 mm² including bonding pads while the active circuit area is 0.05 mm².