Applied Electromagnetics

Applied Electromagnetics

Reducing the effect of the transmitter leakage signal on the receiver using the steepest descent gradient adaptation algorithm

Document Type : Original Article

Authors
1 Master's Degree, Imam Hossein University, Tehran, Iran
2 Assistant Professor, Imam Hossein University, Tehran, Iran
Abstract
Strong signals leaking from the transmitter increase the phase noise effect (caused by the local oscillator (LO) signal) and saturate the receiver, affecting the receiver performance. The transmitter signal leakage at the receiver must be eliminated or reduced as much as possible before reaching the RF stage of the receiver. Otherwise, the front-end circuit (low-noise amplifier and mixer section) must have a high dynamic range to receive the information signal against the strong transmitter leakage signal. In this paper, to eliminate the transmitter self-jamming signal on the receiver, the transmitter signal is sampled. Then, by compensating the amplitude and phase of the eliminating or pseudo-jammer signal, the amplitude and phase of this signal converge towards the amplitude and phase of the strong leakage signal, and the maximum elimination of the transmitter's strong leakage signal as self-jamming (jammer) occurs on the receiver. According to Figures (19 and 20), the gradient of the amplitude and phase coefficients in terms of the number of samples taken from the self-jamming signal using the steepest descent algorithm converged with less sampling, less time, and a higher slope of the curve, while in the reference method, the convergence of the amplitude and phase coefficients is not expressed and displayed. The convergence time of the steepest descent algorithm for the fastest downward slope is 68 µs. Also, the amount of elimination of the self-jamming signal in terms of phase is performed unstable and in more time, and an average of 44 dB of elimination is achieved. While in the innovative and new adaptive method based on the steepest descent algorithm algorithm, 51 dB of self-jamming signal from the transmitter on the receiver was eliminated, which is about 7 dB of elimination improvement compared to the reference method.
Keywords

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Volume 13, Issue 2 - Serial Number 31
Autumn and Winter
February 2026

  • Receive Date 10 November 2025
  • Revise Date 02 January 2026
  • Accept Date 29 January 2026
  • Publish Date 20 February 2026