@misc{9224642,
  abstract     = {{Strong narrowband interference can significantly degrade the sensitivity of wideband receivers by driving front-end circuitry into nonlinear operation. This thesis presents the design, fabrication, and measurement of a 2 – 4.4 GHz electrically tunable varactor-based bandstop filter that can follow and block such narrowband interference before it causes problems in the receiver. It was developed using circuit and electromagnetic co-simulation with parametric optimization before fabrication on a PCB. The measured notch depth is at least 24 dB across the tuning range and exceeds 60 dB at some frequencies. Anti-series varactor placement was used to reduce even-order nonlinearities, achieving harmonic distortion IIP2 > 41 dBm. Cross-modulation is −70 dBc for a desired signal at 3500 MHz with a 0 dBm in-notch interferer at 2800 MHz. For the same notch, IMD3 IIP3 = 47.3 dBm at 2600 MHz, and IIP3 = 23.3 dBm at 3000 MHz. Measured results suggest that the presented tunable bandstop filter can preserve receiver sensitivity in the presence of strong narrowband interference.}},
  author       = {{Förare, Harald}},
  language     = {{eng}},
  note         = {{Student Paper}},
  series       = {{Series of Master's theses}},
  title        = {{Design and Measurement of a 2 – 4.4 GHz Tunable Bandstop Filter for Interference Rejection}},
  year         = {{2026}},
}