Observation of the Inverse Doppler Effect

Abstract

We report experimental observation of an inverse Doppler shift, in which the frequency of a wave is increased on reflection from a receding boundary. This counterintuitive effect has been produced by reflecting a wave from a moving discontinuity in an electrical transmission line. Doppler shifts produced by this system can be varied in a reproducible manner by electronic control of the transmission line and are typically five orders of magnitude greater than those produced by solid objects with kinematic velocities. Potential applications include the development of tunable and multifrequency radiation sources.

Reversed and Anomalous Doppler Effects in Photonic Crystals and other Time-dependent Periodic Media

“…This frequency shift can also have unusual magnitudes. Recently, this theoretical prediction was confirmed by an experimental observation of a reversed Doppler shift from a shock-like wave propagating through a periodic electrical transmission line [1]. While the experiment by Seddon and Bearpark was performed in an electrical transmission line rather than a photonic crystal, the physical origin of the effect in these two systems is closely related.…”

“…One of these explanations is due to SB [1,23] and the other is our theory described in the previous sections and in previous work [15,24]. These two theories provide quantitatively identical predictions in conditions of the experiment of SB, but provide differing predictions in other experimental regimes.…”

“…Seddon and Bearpark (SB) have recently observed a reversed Doppler effect in an electrical transmission line [1]. Rather than a photonic crystal, a 1D radio-frequency electrical transmission line comprised of coupled inductor-capacitor resonators was utilized.…”

“…Photonic crystals [1][2][3][4], or periodic dielectric media, have received much recent attention as a way to control the propagation of electromagnetic radiation on length scales comparable to the wavelength of the radiation. This paper focuses specifically on the dielectric mirror or "multi-layer stack" type of photonic crystal consisting of a 1D structure of alternating layers of different dielectric materials.…”

Reverse Doppler effect in left-handed travelling-wave field-effect transistors

“…This phenomenon is presently called the reverse Doppler effect. Several platforms have been reported to observe this effect for acoustic [2], radio frequency [3,4], and optical [5] waves. Recently, we found that travelling-wave field-effect transistors (TWFETs), originally introduced by McIver in 1965 [6], can support shock waves by applying properly designed decreasing and increasing kink-like voltages to the drain and gate lines, respectively [7].…”