This Small Business Innovation Research Phase I program will demonstrate a novel chip-scale magneto-acoustic spin wave (MASW) circulator for use in S-band applications. The MASW concept is based on the velocity non-reciprocity of surface acoustic waves in Aluminum doped Nickel-Zinc ferrite. The program will first simulate and demonstrate the necessary concepts in a simpler, but no less critical device: a microwave isolator. Upon successful demonstration of the isolator, the circulator will be built and tested. The program will also demonstrate the ability to integrate the MASW with RFICs. The integration process will be demonstrated by solder bumping and flip-chipping the MASW onto a test chip. This will allow for measuring the performance of the MASW when integrated, taking into account the effects of the ball soldered connections. The combination of the demonstrated devices and their flipchip integration will result in integration with a GaN-based RFIC design to provide a low-cost, superior front end component in the Phase II program.
Benefit: The use of microwave and RF communications has been exponentially increasing over the last several decades. This has resulted in an environment full of interference challenges for receivers. While power amplification and digital signal processing (DSP) can address a lot of the issues, progressively more complicated channel coding has limited these capabilities. It is then desirable to have most of the filtering and signal isolation on the front end prior to DSP. Additionally, there are significant challenges in achieving large reductions in size, weight and cost as most state-of-the-art front end components are wavelength limited and rely on cumbersome ferrite materials. This program aims to break the scaling trend through the use of acoustic waves where typical feature sizes are significantly smaller and lighter weight than todays components. Also, the proposed technology relies on existing semiconductor processes, such as metallization and lithography, greatly reducing the cost. Success of this program will usher in a new generation of RFIC components and allow for novel deployment in the military and commercial sectors.
Keywords: Flip-chip, Flip-chip, surface acoustic waves, Microwave circulator, GaN integration, NiZn ferrite, RF components, spinwaves, Yttrium Iron Garnet
