Electrical Balance Duplexer Field Trials in High-Speed Rail Scenarios

Leo Laughlin, Chunqing (Jack) Zhang, Mark Beach, Kevin Morris, John Haine

Research output: Contribution to journalArticle (Academic Journal)peer-review

8 Citations (Scopus)
322 Downloads (Pure)


Electrical balance duplexers (EBDs) present a potential alternative to the fixed frequency duplexing filters used for frequency division duplexing in cellular handset radio frequency front-ends. However the transmit-to-receive (Tx-Rx) isolation can be affected by interaction between the antenna and the environment, and therefore the EBDs balancing impedance must adaptively track time domain antenna impedance variation. A rail scenario presents a potentially demanding use case for an EBD, as fast moving trains in the vicinity of the antenna may cause dynamically changing reflections which can be received as self-interference. In this paper, measured dynamic antenna reflection coefficients at 745 MHz and 1900 MHz from train mounted antennas are included in EBD circuit simulations in order the investigate the resulting variation in Tx-Rx isolation, and determine requirements for balancing impedance adaptation. This paper also presents results from rail based field trials of a hardware prototype EBD which implements real time antenna impedance tracking. Results show that the rail scenario does result in variation in Tx-Rx isolation, but that re-balancing the EBD at intervals of 5 ms was sufficient to maintain >50 dB isolation for ~95% of the time.
Original languageEnglish
Pages (from-to)6068-6075
Number of pages8
JournalIEEE Transactions on Antennas and Propagation
Issue number11
Early online date1 Sep 2017
Publication statusPublished - 1 Nov 2017


  • Duplexers
  • Electrical Balance Duplexer
  • Self-interference cancellation
  • 5G enabling technologies


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