Phase variable PLL oscillator using imperfect integral loop filter

In recent years, with the spread of the broad band communication, higher frequency is proceeding. In particular, the millimeter-wave with a wide bandwidth has received a lot of attention. The millimeter-wave phased array capable of directional communications by a high gain antenna is necessary so that the free space transmission loss is large [1]. However, the phase shifter needed for the phased array has the large loss in the millimeter-wave band. Therefore, the local phase shifter type or amplifier has an advantage in electric requirements [2]. In this paper, we propose a phase variable phase lock loops (PLL) oscillator using imperfect integral loop filter as the mechanism to enable local signal phase to shift. The circuit configuration to achieve a beamformer by the oscillator array is simple and expected for low power. In the experiment, PLL output phase was shifted by controlling the leak current in the loop filter.