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Single-Ended Oscillation-Based Test Technique for Passive RF Phase Shifters
  • Johannes Venter ,
  • Tinus Stander
Johannes Venter
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Tinus Stander
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Phased array systems have become paramount to the development of next generation wireless communication networks, with errors on phase shifters contributing to beam pointing error. Oscillation-based built-in self-testing (OBIST) of phase shifters may improve on this accuracy. We propose a single-ended oscillation-based test technique for passive RF phase shifters. The method uses a negative resistance oscillator topology, where the phase shifter is used to capacitively load the active negative resistance circuit resulting in a dependency between relative phase shift and output oscillation frequency. Simulation results indicate an average sensitivity of 0.14 MHz/° of phase shift around a nominal 617 MHz output oscillation when testing an X-band reflection-type phase shifter, while the addition of OBT circuitry increases the phase shifter’s mid-band insertion loss by 0.93 dB.