A D-band divide-by-6 injection-locked frequency divider with Lange-coupler feedback architecture in 0.13 µm SiGe HBT

A D-band divide-by-6 injection-locked frequency divider (ILFD) is presented. The basic mechanism of high division ratios frequency divider is investigated. The circuit employs a wideband microstrip Lange coupler, a microstrip delay line and a pair of Cascode transistors to form a feedback loop for enhanced divide-by-6 operation. The proposed ILFD is fabricated with chip size of 0.7 × 0.9mm2 in a 0.13 μm SiGe HBT technology. The losses of WR-6 waveguide and 170-GHz probe in measurement setup are calibrated accurately by employing the open-short-load approach in a terminated two-port network. Through varying the operating voltage, the free-running oscillation frequency of the circuit can be changed, which results in an effective frequency-division locking range of 135 to 150.2 GHz while consuming 5.25 to 14.4mW including the output buffer amplifier. A phase noise of −121.58 dBc/Hz at 1MHz offset is achieved at 150.2GHz.