Design and performance of ultra low phase noise reflection whispering gallery resonator oscillator

Abstract

is 82%, has been increased to 90% as the lower cut-off frequency is further lowered due to insertion of slits in the ground plane. The radiation patterns at the resonant frequencies are measured and are as shown in the Figure 6. From the figures it is observed by inserting slits in the ground plane both H-plane and E-plane radiation patterns are quite closer to omnidirectional. CONCLUSIONSCompact L-shaped notched printed antennas with dual slits for multiband and wideband applications are studied experimentally. Here, the ground plane is kept 2 mm away from the radiating patch. Two types of ground plane effects for the proposed antennas have been studied, which are one with rectangular ground plane and the other with modified ground plane, in which dual slits are introduced in the ground plane. Using rectangular ground plane, wideband and multiband operation is achieved with an overall bandwidth of 6.84 GHz (110%). And by using modified ground plane, the overall bandwidth of this multiband antenna is further increased to 7.86 GHz (114.5%). The over all size of the antenna is quite compact, i.e., 38 ϫ 38 mm 2 .

Low phase‐noise planar oscillators using high‐Q SIW bandpass filter

“…The oscillator is one of the fundamental components in microwave circuits. In recent years, there have been numerous attempts to reduce the phase noise of oscillators, which have some advantages for low cost and improved reliability [1, 2]. Nevertheless, their phase‐noise characteristics are inferior due to the poor Q factor of the resonator.…”

Medium power C‐band array amplifier featured ultra low residual phase noise

“…In a number of articles, it is demonstrated that microwave oscillators based on sapphire whispering gallery resonators, which sometimes also referred as sapphire loaded cavity (SLC) resonators and SiGe hetero-junction bipolar transistors (HBT) possess very low phase noise level [1][2][3]. Commonly in this type of oscillators low power HBTs are employed, so that the output power of these artifacts does not exceed 10s of miliwatts.…”

“…Memory effects are defined as changes of the amplitudes and phases of the distortion components due to the previous signals and commonly observed the asymmetries between the lower and the upper bands for modulated signals [1][2][3][4][5][6][7]. Among various techniques, feedforward methods can be regarded as memoryfree linearizers because they use their error signals to improve the linearity [8].…”