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We present an in-situ antenna characterization method and results for a “low-frequency” radio astronomy engineering prototype array, characterized over the 75–300 MHz frequency range. The presence of multiple cosmic radio sources, particularly the dominant Galactic noise, makes in-situ characterization at these frequencies challenging; however, it will be shown that high quality measurement is possible...
A new cryogenic noise calibration source for radio astronomy receivers is presented. Dissipated power is only 4.2 mW, allowing it to be integrated with the cold part of the receiver. Measured long-term stability, sensitivity to bias voltages, and noise power output versus frequency are presented. The measured noise output versus frequency is compared to a warm noise diode injected into a cryogenic...
Cryogenic evaluation of a 30–50 GHz 0.15-μm InGaAs metamorphic high electron mobility transistor (MHEMT) low noise amplifier (LNA) for radio astronomy applications is presented in this paper. For the on-wafer measurement, the LNA exhibits a bandwidth of 23 GHz with a small signal gain of 20.4 dB. For the cryogenic measurement, the LNA is further assembled in a packaged module. At a cryogenic temperature...
In this paper, the design of a compact planar bandpass filter above a defected ground plane is presented. The filter is designed as a combination of microstrip resonators and exploits the properties of a planar electromagnetic bandgap (EBG) structure patterned unto the ground plane of the printed circuit board material to provide a very wide stopband of up to 5 times the fundamental frequency. The...
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