On determination of conducted RF immunity test methodology for automotive remote keyless entry receivers

The performance of automotive remote keyless entry systems under the influence of conducted RF injection is investigated. An UHF receiver for automotive applications in the 314.9 MHz frequency band was designed to operate with a 100 meter range, and -110 dBm of sensitivity requirements. The UHF receiver was subjected to conducted RF noise by a bulk current injection test technique over the frequency span of 1 MHz - 400 MHz. The bulk current injection RF amplifier is a source of a broadband noise rich in harmonic content. BCI amplifier harmonics occurring within the SAW and IF filter bandwidth of UHF receivers can severely degrade the performance of the UHF sensitive circuits and can cause performance problems. The use of external filters introduced at the output of a BCI RF amplifier to alleviate the impact of the test equipment is measured and discussed.