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Characterizing Multiple Coherent Signals at 75 GHz with Standard RF Hardware for MIMO and 5G Applications



Alexandra E. Curtin, David R. Novotny, Joshua A. Gordon


In wireless communication technology, the growth of 5G and MIMO (multiple-input and multiple- output) systems has revealed a gap in the methods to characterize and calibrate hardware for high frequency and coherent MIMO applications. High frequency (>20 GHz) and multi-beamforming communication applications will be implemented to maximize the use of transmit power and improve data throughput by means of spatial and frequency diversity. For digitally-formed beams from arrays or ad-hoc systems, each system element will require position and complex propagation (phase and amplitude) in order to direct beam pointing and control null positions. We demonstrate the use of off-the-shelf frequency conversion hardware to perfom a complex element calibration by using a 75-GHz signal modulated by a four-bit code transmitted and received through multiple antenna elements. We demonstrate the stability of a single channel and the ability to determine a relative complex offset for additional channels. This complex weighting, along with position and pointing, is needed to characterize coherent MIMO systems Our initial test system uses a modulated WR- 10 vector network analyzer up-converter to generate a modulated 75 GHz signal. The signal is independently received on four coherent WR-15 converters. In the receiver heads, our IF signal is first measured with a high-dynamic-range spectrum analyzer and then later collected with a digital oscilloscope. All the signal generators for the receiver local oscillator (LO) and transmitter(s) RF IN are tied together with a common 10 MHz reference. Characterizing this initial 1x4 system is extensible to multiple-receiver applications. We will use these coherent sources to get full, complex waveform characterization element-by-element in a receiving array. We report on measurement and calibration methods to characterize the response of these systems for continuous waveforms, modulated signals, and multi-frequency applications needed for next genera
Proceedings Title
Proceedings of the 2015 Antenna Measurement Techniques Association
Conference Dates
October 30-November 4, 2016
Conference Location
Austin, TX


Curtin, A. , Novotny, D. and Gordon, J. (2016), Characterizing Multiple Coherent Signals at 75 GHz with Standard RF Hardware for MIMO and 5G Applications, Proceedings of the 2015 Antenna Measurement Techniques Association, Austin, TX (Accessed May 22, 2024)


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Created October 30, 2016, Updated January 27, 2020