A 17.1-17.3-GHz image-reject downconverter with phase-tunable LO using 3/spl times/ subharmonic injection locking

SiGe Radio Frequency ICs for Low-Power Portable Communication

“…A high-step-down transformer developed for a 17-GHz integrated downconverter is shown in Fig. 24(b) [26]. The primary winding is identical to the design of Fig.…”

“…25 [26]. The image rejection of the downconverter can be optimized by adjusting the phase of the LOs generated by a subharmonically injection-locked oscillator incorporating on-chip passive delay lines.…”

Can silicon catch the millimeter wave?

“…This eliminates a passive (off-chip) filter connected between the preamplifier (LNA) and the mixer needed to reject spurious signals at the "image" of the desired signal band in a heterodyne radio, or in a homodyne (direct conversion) receiver. The 17GHz image-reject receiver test IC includes a low-noise amplifier (LNA) and 2 mixers coupled by the step-down transformer [3]. A quadrature local oscillator (LO) generator allows the image rejection of the downconverter to be optimized by adjusting the phase of the LOs generated by a subharmonically injection-locked oscillator incorporating on-chip passive delay lines.…”

Receiver RF Front-End with 5GHz-Band LC Voltage-Controlled Oscillator and Subharmonically-Locked Ring Oscillator for 17GHz Wireless Applications

“…Limiting amplifiers triple the frequency injected from the polyphase filter into each delay-line oscillator stage [6]. The ring oscillator is designed to free-run below the third harmonic of the injection amplifier outputs.…”

“…The 2-stage delay-line ring oscillator uses differential amplifier gain stages (DA in Fig. 1) and asymmetric on-chip LC delay lines [6]. The phase of the ring oscillator outputs can be adjusted by a few degrees on either side of the nominal (very close to quadrature because of on-chip matching of stages).…”