Integrated Wideband Self-Interference Cancellation in the RF Domain for FDD and Full-Duplex Wireless

Jin Zhou, Tsung Hao Chuang, Tolga Dinc, Harish Krishnaswamy

Research output: Contribution to journalArticlepeer-review


A fully integrated technique for wideband cancellation of transmitter (TX) self-interference (SI) in the RF domain is proposed for multiband frequency-division duplexing (FDD) and full-duplex (FD) wireless applications. Integrated wideband SI cancellation (SIC) in the RF domain is accomplished through: 1) a bank of tunable, reconfigurable second-order high-Q RF bandpass filters in the canceller that emulate the antenna interface's isolation (essentially frequency-domain equalization in the RF domain) and 2) a linear $N$-path $G-m$-$C$ filter implementation with embedded variable attenuation and phase shifting. A 0.8-1.4 GHz receiver (RX) with the proposed wideband SIC circuits is implemented in a 65 nm CMOS process. In measurement, $>20\;\text{MHz}\;20\;\text{dB}$ cancellation bandwidth (BW) is achieved across frequency-selective antenna interfaces: 1) a custom-designed LTE-like 0.780/0.895 GHz duplexer with TX/RX isolation peak magnitude of 30 dB, peak group delay of 11 ns, and 7 dB magnitude variation across the TX band for FDD and 2) a 1.4 GHz antenna pair for FD wireless with TX/RX isolation peak magnitude of 32 dB, peak group delay of 9 ns, and 3 dB magnitude variation over 1.36-1.38 GHz. For FDD, SIC enhances the effective out-of-band (OOB) IIP3 and IIP2 to $+\text{25}\text{-}27\;\text{dBm}$ and $+90\;\text{dBm}$, respectively (enhancements of 8-10 and 29 dB, respectively). For FD, SIC eliminates RX gain compression for as high as $-8\;\text{dBm}$ of peak in-band (IB) SI, and enhances effective IB IIP3 and IIP2 by 22 and 58 dB.

Original languageEnglish (US)
Article number7302529
Pages (from-to)3015-3031
Number of pages17
JournalIEEE Journal of Solid-State Circuits
Issue number12
StatePublished - Dec 2015
Externally publishedYes


  • Blocker
  • CMOS
  • SAW-less
  • SI cancellation (SIC)
  • coexistence
  • cross-modulation
  • frequency-division duplexing (FDD)
  • frequency-domain equalization (FDE)
  • full-duplex (FD)
  • receiver (RX)
  • self-interference (SI)
  • transmitter (TX) leakage
  • triple beat
  • wideband

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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