A beam steering and switching antenna array using an oscillator array with coupled type-II phase locked loops

In this paper, an antenna array using an oscillator array with coupled type-II PLLs is proposed. With type-II PLLs, applying only one control voltage to the one end PLL can give the oscillators to precisely have their signals with the desired phase distribution to the radiating elements for beam-steering applications. Switching the output signal of the phase detector (PD) of the middle element in the array to either a non-inverting buffer amplifier or an inverting one, the sum or difference pattern can be achieved. Furthermore, the antenna array operates stably at the frequency of the reference signal.