I. Introduction
Electromagnetic (EM) emissions from carry-on electronic devices can potentially degrade the minimum detectable signal level of important RF-based navigational instruments on board commercial and general aviation aircraft [1]–[3]. In some situations, the interfering signal frequencies may not coincide, but may be very close to the navigational instruments operating frequencies. For example, the lowest frequencies used for VHF omni-directional range (VOR) and instrument landing system (ILS) localizer instruments are just above commercial FM broadcast frequencies. In such cases, the intermodulation distortion (IMD) products are located adjacent to the desired signal spectrum at the output. The IMD products are generated because of nonlinear circuits, such as mixers, within the instruments.