An Area-Efficient CRLH (Composite Right/Left-Handed)-TL Approach to the Design of Rotary Traveling-Wave Oscillator

This letter presents a 23.6-GHz rotary traveling-wave oscillator (RTWO) based on composite right-/left-handed (CRLH) transmission lines. Thanks to the additional design freedom in oscillating frequency offered by CRLH transmission lines, this oscillator becomes more area-efficient by reducing the size of series distributed signal line and eliminating the need of extra drain bias without any trade-off compared with conventional designs. This oscillator is implemented using a standard 0.18- μm CMOS process. Measurement data shows the oscillator provides an oscillating frequency of 23.6-GHz with an output power of -3.6-dBm while the phase noise is -105-dBc/Hz at 1-MHz offset. The test chip, without output buffers, draws 39-mA from a 1.8-V supply. The core circuit area is only 0.36-mm² while the test chip occupies an area of 0.8-mm ² in adding the pads for measurement.