-Design, simulation and measurement of a reconfigurable CMOS RF tuner that can be utilized in the RF front-end of a software defined radio are presented. 0.13µm high Q CMOS varactors controlled by a 22bit shift register are placed periodically on a low loss Coplanar Waveguide (CPW) transmission line to form a 4-11GHz reconfigurable tuner. The monolithic tuner does not use any MEMS devices to achieve the reconfigurability.
-A dual-mode field programmable RF amplifier / mixer is presented. Transistor switches, low loss CPW lines and RF transistors are combined in a 3-stage distributed topology which can operate as either a distributed amplifier or a distributed mixer. Functional reconfigurability is achieved using one bit programming without changing the signal path. The programmable module in its distributed amplifier mode provides a gain of 8dB in a 3-8 GHz bandwidth. When switched to the distributed mixer mode, it shows a measured average conversion gain of 4dB in a 1-16GHz bandwidth. This circuit is fabricated in a standard 130nm CMOS technology and occupies 4 mm×1.2 mm chip area.Index Terms -CPW line, distributed amplifier, distributed mixer, field programmable, RF.
We are reporting a novel carbon nanotube field effect transistor with a poly-Si bottom gate structure. The device has a gate length of 3µm and achieves a unity gain frequency f T of 2.5GHz and a maximum oscillation frequency f max of >5GHz. The high frequency performance of the device is attributed to the ballistic transport of electrons inside the nanotube and is expected to improve by reducing the gate length.Index Terms -nanotechnology, carbon nanotube, field effect transistor, poly-silicon.
Abstract-A mask programmable technology to implement RF and microwave integrated circuits using an array of standard 90-nm CMOS transistors is presented. Using this technology, three wideband amplifiers with more than 15-dB forward transmission gain operating in different frequency bands inside a 4-22-GHz range are implemented. The amplifiers achieve high gain-bandwidth products (79-96 GHz) despite their standard multistage designs. These amplifiers are based on an identical transistor array interconnected with application specific coplanar waveguide (CPW) transmission lines and on-chip capacitors and resistors. CPW lines are implemented using a one-metal-layer post-processing technology over a thick Parylene-N (15 m) dielectric layer that enables very low loss lines ( 0.6 dB/mm at 20 GHz) and high-performance CMOS amplifiers. The proposed integration approach has the potential for implementing cost-efficient and high-performance RF and microwave circuits with a short turnaround time.
We report fabrication and experimental characterization of metallic single-walled carbon nanotube (SWNT) mixers. Metallic nanotubes attached to gate dielectric (SiO2) and suspended nanotubes were fabricated over Poly-Si gate structures. Devices were characterized for their RF mixing performance up to 80MHz. Under identical input signals, the suspended nanotube mixers had about 8 to 13dB higher convergence gain than the devices attached to the gate dielectric.The advantages of using patterned Poly-Si gate for RF mixers are low parasitic capacitance from the pad to SWNT contacts, and compatibility of Poly-Si gate material with subsequent high temperature growth of SWNTs.
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