BAW filter start-up Akoustis Technologies shipped first prototypes of an S-Band BAW bandpass filter for a military radar application. The filter, designed for a 100 MHz passband between 3.5 and 3.9 GHz, achieved low insertion loss with out-of-band rejection greater than 40 dB. The filters, fabricated in the company’s new New York wafer fabrication facility, were assembled in a custom, 2.5 mm x 2 mm x 0.8 mm package — an 80 to 90 percent reduction in size compared to conventional cavity or integrated passive device (IPD) filters.

The prototypes fulfill an order Akoustis received in December 2016 for the engineering development and initial delivery of BAW filters for this application, which could lead to a production ramp in 2018. Akoustis did not disclose the customer, except to say the company “is a well-established OEM specializing in non-mobile communication systems with annual revenue of more than $1 billion.”

Akoustis is developing single crystal BAW filters, claiming single crystal piezoelectric materials provide more bandwidth, higher operating frequency and greater output power than polycrystalline technology, which is used by Broadcom and Qorvo. Single crystal piezoelectric materials have high thermal conductivity along the path of heat flow, which improves the power handling capability of the filter.

Jeff Shealy, CEO of Akoustis, said, “These new BAW filters, which shipped to our second customer, allow system miniaturization and cost reduction by reducing the radar element footprint size. The passband frequency above 3.5 GHz is also synergistic with our ongoing filter development for high-growth markets, including 5G mobile, 5 GHz Wi-Fi router and CBRS (Citizens Broadband Radio Service), where BAW filters are expected to be unrivaled in performance and size.”