While there have been many years of research on the acoustoelectric effect, there has not been a successful approach or demonstration to provide a manufacturable, continuous wave (CW) acoustoelectric amplifier (AEA) with insertion gain. This letter will present the results of a 169.5-MHz surface acoustic wave (SAW) delay line on 128YX lithium niobate with an embedded monolithic coupled AEA (CAEA) demonstrating a terminal gain of 1.2 dB. The impedance-matched delay line without the CAEA has an insertion loss of 4.6 dB, and with the operational CAEA, the measured gain is 1.2 dB, yielding a net insertion gain of 5.8 dB. The CAEA uses approximately 137 mW dc power at the current peak operational gain. This letter will present experimental results of device performance and discuss the new embodiment for achieving the net insertion gain.

Technology advances provide new processes for the fabrication and application of novel materials to acoustoelectric devices. An important advancement would be the ability to produce practical integrated SAW AE amplifiers. Notably for practical applications, devices will need to be capable of operating with a continuous drift field applied rather than the most often-cited timed pulse approach and be cheaply manufacturable. With ultra-high mobility materials, such as graphene, power reduction can be achieved with the asymmetrical AE effect under a constant applied drift field. This paper will present a new embodiment of a graphene-based AE structure on LiNbO3. The first part of the paper will discuss the theory behind the SAW AE amplifier, including the critical film parameters for the maximum gain. The second part will present a new design and results from recent research efforts to conform graphene to have more ideal thin film parameters for the AE effect

Surface acoustic wave (SAW) acoustoelectric (AE) theory and device embodiments have been demonstrated from the 1960s to the present. Technology has greatly advanced in new materials, growth and deposition, and nano films offering new opportunities for AE effects. The ability to produce a practical integrated SAW AE amplifier in filters and resonators would provide new opportunities for SAW RF filters and oscillators. In particular, the AE amplifier is one component of producing a SAW-based simultaneous transmit and receive (STAR) radio at approximately 1 GHz using spread spectrum RF filtering. This paper will present research efforts on development of a thin film AE amplifier on LiNbO 3 . The first part of the paper will discuss the boundaries and coupled-interactions of the many design parameters for practical AE thin film amplifiers. The second part of the paper will provide the most recent results of the AE amplifier research efforts using graphene on lithium niobate.

Experimental results of the measured surface acoustic wave (SAW) acoustoelectric effect (AE) using single-layer thin-film graphene on 128°, -cut, and -propagating lithium niobate (128-LN) are presented. The use of an AE amplifier in SAW communication devices, especially in gigahertz bands, could make fundamental advancements in radios, sensors, and other applications. Experimental results at 1350 MHz show the delay line asymmetry of 3 dB, given as the ratio of the forward versus reverse peak SAW frequency response, with an applied dc voltage on the graphene film.

Passive, wireless surface acoustic wave (SAW) sensor systems can be approached from a radar perspective, where the SAW device is thought of as a cooperative target. This paper investigates the use of a commercial-off-the-shelf software defined radio to interrogate wireless SAW sensors with a randomly generated interrogation pulse. The USRP B200mini is utilized as the transceiver platform with custom field-programmable gate array (FPGA) modifications to generate the random interrogation waveform and provide synchronization and buffering to the received signal. Each transmit sample bit in the FPGA is fed by an independent linear-feedback shift register, which generates pseudo-random I and Q samples for the interrogation pulse. An RF daughterboard has also been developed and integrated with the B200mini to increase the transmit power, provide filtering of the RF signals, and switch a signal antenna between the transmit and receive channels. Radio control and matched filter correlator post-processing are accomplished using Python. Design and implementation details for the FPGA modifications, RF daughterboard, and post-processing are discussed. The system is demonstrated by wirelessly interrogating SAW temperature sensors at 915 MHz.