This Small Business Innovation Research (SBIR) Phase I project will investigate the feasibility of using piezoelectric aluminum nitride contour mode resonator (CMR) filters to replace surface acoustic wave (SAW) and monolithic crystal filters (MCFs) at very high frequencies (VHF). Despite rapid innovation in transceiver blocks such as the radio frequency (RF) front-end and baseband processor, intermediate frequency (IF) bandpass filter technology has been relatively static for decades. Legacy filters, which are made from exotic crystalline substrates, remain bulky and expensive, and cannot meet industry demand for miniaturized high performance solutions. CMR filters, which are processed on silicon substrates and have their operating frequency set by lithographically defined features, can be orders of magnitude smaller and less expensive than and offer improved performance over legacy technologies. The research objective is to demonstrate VHF CMR filters that meet customer requirements, and will be accomplished by improving the resonator design to increase the quality factor, implementing filter design enhancements, and establishing a microfabrication process suitable for manufacturing. These improvements will result in filters with insertion loss less than 2 dB, rejection greater than 80 dB, direct 50 W matching, high power handling, excellent phase linearity, and a highly scalable microfabrication process.
The broader impact / commercial potential of this project includes contributions to technological understanding by supplementing the body of knowledge in the fields of RF micromachined electromechanical systems (MEMS), electro-acoustics, and thin-film fabrication technology, and by enabling paradigm shifts in wireless transceiver design. The proposed IF CMR filter solutions provide a compelling value proposition to communication electronics manufacturers by offering up to several orders of magnitude reduction in component size and weight, by enabling lower power consumption and higher sensitivity via reduced filter insertion loss and higher rejection, and ultimately, by costing substantially less than their SAW filter and MCF competitors. The IF filter market understates the true commercial potential since CMR technology is scalable to RF filters and clock resonators and oscillators. The addressable market for CMR IF filters is $250 million annually, and includes the communications, consumer electronics, automotive, industrial, and aerospace / military sectors. Several large electronics companies have written formal letters of interest in the proposed technology. The proposed CMR technology has broad societal impact by facilitating the proliferation of low cost, highperformance wireless communication devices and through job and wealth creation.
