S-band Oscillator using ForeS Resonator

The modern communication systems require low cost, low phase noise local oscillators. The dielectric resonator oscillators have been widely used, but these are not compatible to monolithic microwave integrated circuit (MMIC), because the dielectric resonators have height dimension. On the other hands, the left-handed (LH) resonators have many advantages over traditional ones. First, they have planar profile, second, they are cheap to implement, and third, they have high quality factors. Among them, the high quality factor property made the microwave oscillators utilizing left-handed resonator as its resonator one of the promising research areas, because of their high Q led to excellent phase noise characteristic of microwave oscillators [1-4]. The phase noise characteristic of an oscillator is strongly dependent on the quality factor of its resonator [5]. But the quality factor of a microstrip resonator is inherently limited by the substrate loss and conductor loss of microstrip structure. Despite this limitation, the left-handed resonators like ForeS show relatively high quality factor even when it is implemented in microstrip structure, which can be utilized for low phase noise oscillator application. In this paper, a novel low phase noise oscillator using ForeS resonator is presented for the first time. The ForeS resonator which is left-handed, has planar profile and high quality factor that lowers the cost and phase noise of the oscillator, respectively.