  Resonant feedback circuits are proposed as an alternative to normal modes of
conducting wall cavities or lumped circuits in searches for hidden sector
particles. The proposed method offers several potential advantages over the
most sensitive axion searches to date, that employ cavity resonators, including
coverage of a wider range of axion masses, the ability to probe many axion
masses simultaneously, and the elimination of experimentally troublesome
mechanical tuning rod mechanisms. After an outline of the proposed method, we
present a noise budget for a straw-man experiment configuration. We show that
the proposed experiment has the potential to probe the axion mass range 2-40
micro-eV with 38 days of integration time. Other existing and proposed resonant
searches for hidden sector particles may also benefit from this approach to
detection.
