Shih-Fong Chao

A 50 to 94-GHz CMOS SPDT Switch Using Traveling-Wave Concept

A fully integrated single-pole-double-throw transmit/receive switch has been designed and fabricated in standard bulk 90-nm complementary metal-oxide semiconductor (CMOS) technology. Traveling wave concept was used to minimize the insertion loss at higher frequency and widen the operating bandwidth. The switch exhibits a measured insertion loss of 2.7 -dB, an input 1-dB compression point (input P1 dB) of 15 dBm, and a 29-dB isolation at the center frequency of 77 GHz. The total chip size is only 0.57 times 0.42 mm 2 including all testing pads. To our knowledge, this is the first CMOS switch demonstrated beyond 50 GHz, and the performances rival those monolithic microwave integrated circuit switches using standard GaAs PHEMTs

Electronically Switchable Bandpass Filters Using Loaded Stepped-Impedance Resonators

Stepped-impedance resonators with diodes loaded at one end are used to develop switchable bandpass filters in this paper. The loaded diodes are used to switch the resonance conditions of the stepped-impedance resonators. The equations for resonance conditions of the stepped-impedance resonators with different loads at one end are derived and discussed. With these derived equations, the switchable filters can be easily designed and synthesized using the coupled-resonator filter theory. When the switchable filter is switched on, a bandpass filter response with a wide stopband rejection is achieved by making the on-state coupled resonators have the same fundamental resonant frequency, but different higher order resonant frequencies. When switched off, a high and wideband isolation is obtained by properly misaligning the resonant modes of the off-state resonators. The design concept is demonstrated by two single-pole-single-throw fourth-order Butterworth-type switchable microstrip bandpass filters, which utilize two and three switched stepped-impedance resonators, respectively. Finally, a compact single-pole-double-throw switchable microstrip bandpass filter using common resonators is demonstrated for wireless communication applications

A DC-11.5 GHz Low-Power, Wideband Amplifier Using Splitting-Load Inductive Peaking Technique

A DC-11.5 GHz low-power amplifier is developed in commercial 0.13 mum, CMOS technology. This amplifier design is based on a three-stage shunt-feedback inverter-configuration with splitting load inductive peaking technique. The peaking inductor is placed at the gate of the nMOS to compensate gain roll-off of the inverter stage and extend its operating bandwidth. This amplifier achieves a gain flatness of 13.21 dB from dc to 11.5 GHz with I/O return losses better than 17 dB at a power consumption of 9.1 mW. The measured noise figure is less than 5.6 dB between 1-11 GHz. The output P1 dB is 8 dBm and input third-order intercept point is 10 dBm. The total chip size is 0.34 mm2 including all testing pads, with a core area of only 0.08 mm2.

A Low Power Folded Mixer for UWB System Applications in 0.18-

This letter presents a wideband mixer using a commercial 0.18-mum CMOS technology process for ultra-wideband (UWB) system applications. To achieve wideband frequency response and low dc power consumption for UWB system applications, the folded approach is utilized to reduce supply voltage as well as dc power consumption, and wideband input matching network is used to achieve wideband frequency response. The measured results show that the proposed mixer demonstrates a wideband frequency response from 0.2 to 16GHz with a conversion gain of better than 5.3dB. The dc power consumption is 15mW under a supply voltage of 1.8V, with a compact size of 0.68mmtimes0.65mm

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A 40-GHz monolithic microwave integrated circuit (MMIC) single-pole-double-throw and multiple-port bandpass filter-integrated switches based on electronically switchable resonators are proposed. The proposed multifunction chip integrates a multiple-port switch with bandpass filter functions in a single chip. The switchable resonators are formed by quarter-wavelength stepped-impedance resonators with passive HEMT loading at one end. By properly allocating the resonant frequencies of the resonators in their on and off modes, a filter-integrated switch can perform a bandpass response with spurious suppression in the on state and achieve wideband isolation in the off state. The technique of using shared resonators is also introduced in the circuit design to reduce the overall circuit size. The results show the proposed circuits successfully integrate a MMIC switch with bandpass filter functions into a single circuit component.

m CMOS Technology

This paper discusses different topologies for millimeter-wave (MMW) multiple-port switches, and analyzes the insertion loss, isolation, and limitation of bandwidth. It is observed the performances of a MMW multiple-port switch are decided by both multiple-port topology and the structure of the constituted unit single-pole-single-throw switches, but dominated by its topology. To verify the analysis, two types of multiple-port switch are designed, one is a distributed switch and the other is based on a filter-integrated switch, using different topologies. The net-type multiple-port topology based on a distributed switch demonstrates a measured insertion loss of 4-5 dB with isolation better than 25 dB in 48-65 GHz. In 43-66 GHz, the binary-ring multiple-port topology based on a filter-integrated switch shows a measured insertion loss of 3-4.5 dB with isolation better than 30 dB.

40-GHz MMIC SPDT and Multiple-Port Bandpass Filter-Integrated Switches

Stepped-impedance resonators (SIR) with HEMTs loaded at one end are used to develop a 40 GHz MMIC SPDT filter integrated switch. The HEMTs are used to switch the resonant frequencies of the loaded stepped-impedance resonators. At on-state, the resonators resonate at the same center frequency to pass the RF signal. With the coupled-resonator filter theory, the filter response could be easily designed and synthesized. At off-state, the resonant frequencies of the resonators between input and output ports are staggered to block the RF signal. In this paper, a compact 40-GHz MMIC single-pole-double-throw (SPDT) switch with integrated a third-order bandpass filter is demonstrated. At thru-port, a bandpass filter response with measured insertion loss of 3.1 dB at the center frequency is obtained. At the isolated-port, an isolation of higher than 30 dB is also obtained. The proposed circuit successfully combines an SPDT switch and a bandpass filter into a single circuit component, and makes a high level of MMIC integration become possible.

Topology Analysis and Design of Passive HEMT Millimeter-Wave Multiple-Port Switches

This paper presents the design and implementation of a 5-6 GHz CMOS variable-gain low noise amplifier (VGLNA) for IEEE 802.11a WLAN application, fabricated on TSMC 0.18-mum 1P6M standard CMOS process. In this design, miniature chip size and wide gain-control range are achieved by using helix-stacked inductors and current steering technology, respectively. This VGLNA exhibits a noise figure of 3.1 dB, small signal gain of 19 dB, and IIP3 of -9 dBm while in its high gain mode. A gain of -19 dB with IIP3 of -4 dBm were measured while switching into its low gain mode. The chip size is only 0.56 mm2