CMOS reconfigurable circuits: Integrated mask programmable and field programmable RF circuits

Laleh Rabieirad, Purdue University

Abstract

The trend of today's RF and microwave market is towards low cost, multi-functional and high performance systems. This research presents solutions to reduce the cost and turn-around time of RF integrated circuits by focusing on novel design approaches for implementing programmable circuits. Two main approaches are discussed; mask programmable RF arrays and field programmable RF arrays. In the mask programmable technology a complementary metal oxide semiconductor (CMOS) transistor array is used as the basic building block for various RF and microwave circuit implementations. A simple post-CMOS processing technology that utilizes room temperature deposited Parylene-N with low permittivity (K=2.4) and extremely low loss (Loss Tangent < 6×10-4) is introduced. Parylene-N serves as a dielectric material to achieve high performance programmable interconnects, inductors and coplanar waveguide (CPW) transmission lines on the CMOS substrate. The interconnect programmability feature enables implementing various types of passive devices on Parylene-N. Application specific narrowband and wideband RF and microwave circuits are achieved only by changing the top metallization and vias (mask programming). 90nm and 0.13μm RF transistor arrays in standard CMOS technology are used to design state of the art RF amplifiers in the frequency range of 4-22GHz. To implement field programmable RF and microwave circuits that can be dynamically programmed through software, several approaches are proposed. Integrated programmable tuners using CMOS varactors as well as transistor/capacitor pairs are implemented in standard 0.13μm CMOS technology. By digitally controlling the state of varactors or transistor switches, impedance of a low-loss shielded CPW transmission line is varied to 222 or 220 different impedances. A 4-5.3GHz programmable RF receiver implemented in this thesis is an example of the application of such MEMS-less tuners in RF front-ends of software defined radios. Finally, a fully integrated field programmable dual-state circuit is implemented for the first time in 130nm CMOS technology. A 3-stage distributed topology using shielded CPW lines and transistor switches is designed to operate as either distributed amplifier or distributed mixer and is programmed using one input bit.

Degree

Ph.D.

Advisors

Mohammadi, Purdue University.

Subject Area

Electrical engineering

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