R . H . Witvers

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Developments in radio astronomy instrumentation drive the need for lower cost front-ends due to the large number of antennas and low noise amplifiers needed. This paper describes cost reduction techniques for the realization of antennas and low noise amplifiers in combination with a noise budget calculation for array systems in the absence of cryogenic(More)
A 0.18 mum CMOS low noise amplifier (LNA) achieves sub-1 dB noise figure over more than an octave of bandwidth without external noise matching components. It is designed for a future radio telescope, requiring millions of cheap LNAs mounted directly on phased array antenna elements. The short distance between antenna and LNA and low frequency below 2 GHz(More)
The sensitivity of antenna systems increases with increasing active area, but decreases at higher noise figure of the low-noise amplifier (LNA). Cooling the LNA locally results in significant improvement in the gain and in lowering the noise figure of the LNA. Micromachined Joule-Thomson (JT) coolers can provide a cryogenic environment to the LNA. They are(More)
Aperture array technology is one of the candidate technologies for the 500 MHz to 1500 MHz frequency range of the SKA. The feasibility and low noise potential of aperture arrays have been demonstrated with small test systems before, e.g. with a 50 K system noise temperature, measured on a 1 m<sup>2</sup> prototype tile in 2010. However, further reduction of(More)
This paper discusses low noise room temperature LNAs with application in the SKA-mid frequency range between 400 MHz and 1500 MHz, using recently obtained measured noise temperatures close to 20 K. It also presents and compares results for measured minimum transistor noise temperatures at room temperature, with values below 10 K.
Recent experimental results for the sensitivity of aperture arrays at room temperature show 40 K array noise temperatures over the frequency range from 1000 MHz to 1500 MHz. Further reduction of array noise temperature is important to comply with the SKA sensitivity requirements at affordable cost. Furthermore the frequency range should be extended to a(More)
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