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A compact circularly polarized shorted annular stacked patch antenna has been proposed for global navigation satellite system (GNSS) in this paper. The antenna has been designed to operate for the satellite navigation frequencies including GPS, GLONASS, Galileo and Compass (1100MHz–1600MHz). Dual layer strip lines which being composed of one broadband 180° hybrid and two wideband 90° hybrids are introduced...
It is well known that mutual coupling effect and problems exist between transmitting and receiving antennas. One factor is the coupling effect between antennas and masts. It can be more than 1 dB for omni-directional antennas with vertical polarization. This effect can be improved by utilizing the average method of changing distance between antennas and antenna mast. According to the reference site...
A micromechanical displacement amplifier comprising two asymmetric resonator array composites coupled by a quarter-wavelength beam has been demonstrated that permits specification of gain factor by mere (digital) selection of an appropriate ratio of the number of resonators in an input array to that in an output array. Like the method, this displacement gain circuit is a key enabler for resoswitch-based...
Quality factors as high as 362,768 have been measured for 61-MHz polysilicon wine-glass disk micromechanical resonators operated at cryogenic temperatures down to 5K. The measured results not only represent a ~2.5times increase in Q over the room temperature value, equivalent to a nearly 10-dB improvement in phase noise; but also provide some limited insight into the intrinsic material damping and...
A statistical comparison between the resonance frequency variations of stand-alone micromechanical disk resonators and mechanically-coupled array composites of them reveals that mechanically-coupled arraying of on-chip micromechanical resonators can very effectively enhance the manufacturing repeatability of resonance frequencies. In particular, twenty 3-disk resonator array-composites on a single...
A CMOS micromixer for 3-5 GHz UWB receivers is developed in this paper, which employs a modified class-AB input stage so as to achieve high linearity and 50 Omega input matching with single-ended to differential conversion. A LO buffer and an output buffer are integrated in it for on-wafer testing. Our measurement results show that, with a 50 Omega output loaded, it can achieve 5 dB gain in power...
This study provides two noncontact and realtime optical measurement methods to assess the displacement, natural frequencies, and mode shapes of a vibrating piezoelectric material. The methods are carried out using amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI) and laser Doppler vibrometer (LDV), which are full-field and point-wise displacement measurement, respectively....
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