Aluminum nitride MEMs and CMOS IC co-design for multi-frequency reconfigurable wireless communications

To ultimately realize efficient spectral utilization, low power consumption and high level integration for next-generation wireless communication systems, a novel radio-frequency (RF) architecture is proposed and key integrated circuit (IC) components are co-designed with Micro-Electro-Mechanical Systems (MEMS) based on the emerging piezoelectric Aluminum Nitride (AIN) contour-mode RF MEMS technology. This unconventional RF architecture has the potential to unify all different wireless communication standards into a single transceiver system that performs channel selection and frequency synthesis directly at RF frequencies. For this purpose, multi-frequency (100 MHz to 1.3 GHz) channel-select MEMS filters have been demonstrated with low insertion loss (∼ 2.3 dB), narrow bandwidth (∼ 0.2%) and high out-of-band rejection (∼ 60 dB) by self-coupling two-port piezoelectric AIN contour-mode resonators (CMRs) into higher-order band-pass systems. Using appropriately designed one-port AIN CMRs, multi-frequency (100 MHz to 1.9 GHz) complementary metal-oxide-semiconductor (CMOS) oscillators have been implemented with low phase noise (e.g ., –140 dBc/Hz at 100-kHz offset frequency for an oscillation frequency at 1 GHz). These unprecedented performances are made possible by the high quality factor (Q) and large power handling capability of the piezoelectric AIN MEMS CMRs. In order to accommodate multi-frequency MEMS components for system reconfiguration and optimization, a tunable transceiver front-end design based on a novel tunable-supply circuit technique is proposed and key components are experimentally demonstrated. Every building block (radio frequency amplifier, intermediate frequency amplifier, mixer and envelope detector) of the transceiver system is realized using a universal amplifier module called the tunable-supply inverter amplifier (TSIA), so that the implementation is easily scaled across different CMOS technology nodes. As a proof of concept, such a multi-frequency tunable receiver has been designed and fabricated in the IBM 65-nm CMOS process, and the experimental results show record-high receiver sensitivity of –85 dBm at 272-MHz operation with a data rate of 100 kbps and low power consumption of 468 μW, even when the local oscillator signal is provided by a multi-frequency reconfigurable MEMS-CMOS oscillator based on piezoelectric AlN CMRs. All these components, from MEMS devices to oscillator circuits and receiver systems are compelling demonstrations of the level of innovation that can be attained by the co-design of MEMS and CMOS IC. The intelligent combination of the two technologies will not only address what were considered insurmountable challenges in the realization of channel-select front ends, but will also enable reconfigurable, tunable, low-power and broad-spectrum transceivers