Meng Miao

On the Development of an Integrated CMOS-Based UWB Tunable-Pulse Transmit Module

A novel low-cost low-power fully integrated tunable transmit module composed of a tunable CMOS monocycle pulse generator and compact uniplanar antenna was designed, built, and tested for ultra-wideband (UWB) impulse systems. The CMOS tunable pulse generator integrates a tuning delay circuit, square-wave generator, impulse-forming circuit, and pulse-shaping circuit in a single chip using a standard low-cost 0.25-mum CMOS process. It can generate a monocycle pulse and Gaussian-type impulse (without the pulse-shaping circuitry) signals with tunable pulse duration. A compact uniplanar UWB antenna was also developed and integrated directly with the CMOS pulse generator chip to form the complete integrated tunable UWB transmit module. Measured results show that the CMOS tunable pulse generator can produce a 0.3-0.6-V peak-to-peak monocycle pulse with 140-350-ps tunable pulse duration and a 0.5-1.3-V peak-to-peak impulse signal with 100-300-ps tunable pulse-duration, and the uniplanar antenna has less than a 18-dB return loss and is suitable for transmitting/receiving UWB time-domain impulse signals covering the entire UWB bandwidth of 3.1-10.6 GHz. Good agreement between measured and calculated performance is also achieved. The UWB transmit module was experimentally characterized and its performance is verified. This UWB module finds applications in various time-domain UWB systems including wireless communications and radar

A Novel Multilayer Aperture-Coupled Cavity Resonator for Millimeter-Wave CMOS RFICs

A novel millimeter-wave cavity resonator, completely compatible with commercial CMOS fabrication techniques, has been designed and fabricated in a 0.25-mum CMOS process and tested. The resonator employs a capacitively loaded cavity topology effectively implemented using the CMOS multimetal-layer and via-hole structure. The CMOS capacitively loaded cavity resonator, including two coupling apertures and microstrip feed lines, occupies an area of 2 mmtimes1.4 mmtimes6.28 mum, which is much smaller than the cavity resonator designed without a capacitive load at the same resonant frequency. It resonates at 30 GHz with a corresponding insertion loss of 2 dB and unloaded quality factor of 22.2. The resonant-frequency reduction is approximately 50%, as compared to that without the capacitive load. The design and performance of a new CMOS coupling aperture, which is useful as a coupling mechanism and a vertical interconnect for highly dense millimeter-wave CMOS RF integrated circuits (RFICs) are also presented. The developed low-loss and compact CMOS cavity resonator can be used to realize various millimeter-wave on-chip passive components such as wideband bandpass filters and diplexers and is suitable for direct integration with other CMOS circuits on a single chip. It is attractive for CMOS RFIC design at millimeter-wave frequencies

Recent development of SRD- and FET-based sub-nanosecond pulse generators for ultra-wideband communications

Various low-cost, compact planar ultra-wideband (UWB), ultra-short pulse generators have been developed using step recovery and PIN diodes and MESFET. These include fixed and electronically tunable pulse generators. Fixed pulses ranging from 115 to 300 ps and tunable pulses Varying from 300 to 800 ps have been demonstrated experimentally and theoretically. Good agreement between measured and calculated results is also achieved. These pulse generators find applications in UWB communications systems, both transmitter and receiver.

Fundamentals of UWB Impulse Systems

This chapter covers the fundamentals of UWB impulse systems operating across or within the unlicensed UWB frequency band of 3.1–10.6 GHz. It provides the essence of UWB impulse systems including the spectrum mask, advantages and applications of UWB impulse systems, UWB impulse signals including Gaussian impulse, doublet pulse and monocycle pulse, modulations including PPM, PAM, OOK and BPSK, UWB impulse transmitters and receivers, and UWB antennas.

UWB Impulse Transmitter Design

This chapter presents the design of CMOS UWB tunable sub-nanosecond impulse and monocycle-pulse BPSK transmitters. The UWB impulse transmitter produces positive and negative tunable impulse signals corresponding to the high- and low-level modulation signals, respectively. The positive and negative impulse signals have amplitudes of 0.8 and 0.6 V with tunable pulse widths from 100 to 300 ps, respectively. The UWB monocycle-pulse transmitter produces monocycle pulse signals of opposite polarities having peak-to-peak amplitudes of about 0.6–0.8 V and tunable pulse widths between 100 and 300 ps. This chapter also covers the design of the CMOS impulse generator and BPSK modulator used in the UWB impulse and monocycle-pulse transmitters. The impulse generator can generate 0.95–1.05 V peak-to-peak Gaussian-type impulse signal with 100–300 ps tunable pulse duration. Moreover, this chapter includes the design of a CMOS monocycle pulse generator, which can produce 0.7–0.75 V peak-to-peak monocycle pulse with 140–350-ps tunable pulse duration.

UWB Uniplanar Antenna

This chapter covers the design and performance of a low-cost, compact UWB uniplanar antenna operating across the entire UWB of 3.1–10.6 GHz, which can be easily integrated with the designed CMOS UWB transmitter and receiver. Especially, various impulse time-domain measurements are conducted to demonstrate the performance and suitability of the designed UWB uniplanar antenna for transmitting and receiving impulse signals that contain all frequency components from 3.1 to 10.6 GHz, which are essential for UWB impulse systems. The UWB uniplanar antenna is further integrated with the previously developed CMOS tunable pulse generator to form the UWB transmit prototype. This UWB transmit prototype can transmit monocycle pulses with pulse duration tunable from 160–350 ps with the impulses supplied from the integrated pulse generator. The received pulses maintain good symmetry with no serious distortion and ringing. The UWB transmit prototype can also transmit signals having shape similar to the first derivative of the monocycle pulses provided by the integrated pulse generator. Both the impulse and monocycle-pulse transmission results clearly demonstrate the workability of the CMOS-based tunable UWB transmit prototype for UWB impulse systems.

An integrated CMOS transmitter-antenna for UWB systems

A new low-cost, low-power fully integrated CMOS transmitter-antenna was designed, built and tested for UWB systems. The CMOS pulse generator can generate monocycle and impulse signals with tunable pulse duration. The UWB antenna is integrated directly with the CMOS chip. The antenna has less than 18- dB return loss and can transmit and receive UWB impulse signals over the entire UWB bandwidth of 3.1-10.6 GHz. The UWB transmit-antenna module can generate and transmit both monocycle pulses from 140 to 350 ps and impulses from 100 to 300 ps.