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Brigham Young University

Faculty Publications

Amplifier noise

Publication Year

Articles 1 - 3 of 3

Full-Text Articles in Engineering

Minimizing The Noise Penalty Due To Mutual Coupling For A Receiving Array, Karl F. Warnick, Leonid Belostotski, Peter Russer Jun 2008

Minimizing The Noise Penalty Due To Mutual Coupling For A Receiving Array, Karl F. Warnick, Leonid Belostotski, Peter Russer

Faculty Publications

For phased array receivers, mutual coupling leads to beam-dependent effective impedances at array element ports. Front end amplifiers can be matched for optimal noise performance for one beam steering direction, but noise performance becomes poor at other steering directions. We analyze this noise penalty in terms of beam equivalent noise temperature for various amplifier noise matching conditions, and develop a new matching condition that minimizes the average beam equivalent receiver noise temperature over multiple beams. For non-beamforming applications such as MIMO communications, we show that noise performance for coupled arrays can be quantified using the spectrum of an available receiver …


Optimal Noise Matching For Mutually-Coupled Arrays, Michael A. Jensen, Karl F. Warnick Jun 2007

Optimal Noise Matching For Mutually-Coupled Arrays, Michael A. Jensen, Karl F. Warnick

Faculty Publications

From classical two-port noise theory, the noise figure of an amplifier is minimized when a source is matched to a particular optimal reflection coefficient at the amplifier input. In this paper, we show that this result extends in a natural way to the multiport case, with a coupled N-port source network such as an array antenna connected by a multiport matching network to the inputs of N low-noise amplifiers. For optimal noise performance, the matching network must decouple the array and present isolated, individually noise-matched ports to the amplifier inputs.


Impact Of Receive Amplifier Signal Coupling On Mimo System Performance, Michael A. Jensen, Matthew L. Morris Sep 2005

Impact Of Receive Amplifier Signal Coupling On Mimo System Performance, Michael A. Jensen, Matthew L. Morris

Faculty Publications

This paper uses a detailed model of multiple input multiple output (MIMO) systems to explore the impact of signal coupling in the receiver front end on communication capacity. The model is applied to assess the performance of a MIMO system with two transmit and receive antennas in a simulated multipath environment for different amplifier coupling levels. The results show that in practical scenarios where simple impedance matching techniques are used, the circuit coupling can reduce the signal-to-noise ratio at the receiver and therefore degrade the achievable MIMO capacity.