Chau-Ching Chiong

Analysis and Design of Millimeter-Wave Low-Voltage CMOS Cascode LNA With Magnetic Coupled Technique

In this paper, the design and analysis of CMOS low-noise amplifiers (LNAs) with a magnetic coupled technique in different cascode topologies are proposed. To minimize the noise figure (NF) and the supply voltage, and to guarantee large 3-dB bandwidth, transformers are designed and placed between the transistors of the cascode devices. Three low supply voltage and wideband LNAs are designed, fabricated, and tested for demonstration. The first LNA uses the magnetic coupled cascode configuration. The second LNA is consisted of magnetic coupled cascode configuration with two amplification stages. The third one-stage LNA is based on the magnetic coupled triple cascode configuration. The first LNA is designed at Q -band while the others are designed at V-band, using 90-nm low-power CMOS technology. The Q-band LNA has a gain of 13.8 dB and an NF of 3.8 dB at 37 GHz, with a power consumption of 18 mW at 1.2-V supply voltage. The V-band cascode LNA has a gain of 17 dB at 57 GHz and an NF of 4.4 dB at 59.5 GHz with a power consumption of 19.2 mW at 1.2-V supply voltage. The V -band triple-cascode LNA has a gain of 13.7 dB at 54 GHz and an NF of 5.3 dB at 59.5 GHz, with a power consumption of 14.4 mW at 1.2-V supply voltage. Compared with the conventional cascode LNAs, the proposed magnetic coupled cascode LNAs have better NF, larger gain bandwidth product, and lower power consumption. The use of the magnetic coupled technique in a multicascode LNA significantly improves the gain performance with a slight degradation of the NF.

A DC-21 GHz Low Imbalance Active Balun Using Darlington Cell Technique for High Speed Data Communications

A DC-21 GHz low imbalance active balun using a 2 mum InGaP/GaAs HBT process is presented in this letter for high speed data communications. A Darlington cell is adopted to enhance 3 dB bandwidth of the proposed active balun. A feedback capacitor is designed to compensate the phase error between differential output ports caused by the different number of stages. The proposed active balun achieves a broad bandwidth of 21 GHz, an average small signal gain of 2.5 dB, a maximum amplitude imbalance of 1.2 dB, and a phase error of less than 5deg. The measured group delays of the balun are lower than 30 ps with low variation. Moreover, an eye diagram with a pseudorandom bit stream of up to 12.5 Gbps is presented. The active balun is appropriate for high speed data communications due to its low imbalance and group delay.

Gain-Bandwidth Analysis of Broadband Darlington Amplifiers in HBT-HEMT Process

Broadband Darlington amplifiers using a GaAs heterojunction bipolar transistor (HBT) high electron-mobility transistor (HEMT) process are reported in this paper. The gain-bandwidth analysis of the Darlington amplifiers using HEMT-HBT, HBT-HEMT, HEMT-HEMT, and HBT-HBT configurations are presented. The bandwidth, gain, input, and output impedances are investigated with transistor size, feedback resistances, and series peaking inductance. The design methodology of the broadband Darlington amplifier in the HBT-HEMT process is successfully developed, and the direct-coupled technique is also addressed for high-speed data communications. Furthermore, two monolithic HEMT-HBT and HEMT-HEMT Darlington amplifiers are achieved from dc to millimeter wave, and successfully evaluated with a 25-Gb/s eye diagram. The HEMT-HBT Darlington amplifier demonstrates the best gain-bandwidth product with good input/output return losses among the four configurations.

Low Insertion-Loss Single-Pole–Double-Throw Reduced-Size Quarter-Wavelength HEMT Bandpass Filter Integrated Switches

This paper proposes a circuit topology which reduces the chip size of single-pole-double-throw (SPDT) quarter-wavelength bandpass filter-integrated switches (FIS). A 40-GHz mHEMT MMIC SPDT switch has been implemented and demonstrates a measured insertion loss lower than 1 dB and an isolation better than 30 dB. Another 50-GHz pHEMT MMIC SPDT achieves 1.5 dB insertion loss and 22 dB isolation. The low insertion loss and high isolation shows that the circuit performance is improved along with the reduction of the size. The systematic design approach of the reduced-size FIS is described, together with the analysis of the insertion loss and isolation.

A GaAs-based HBT 31-GHz frequency doubler with an on-chip voltage

In this paper, a frequency doubler is developed for MMW applications in a GaAs 2-mum HBT process. This balanced doubler adopts the cascode devices to achieve a high conversion gain, with a built-in 180deg reduced-size Marchand balun for fundamental suppression. In addition, because HBT presents a high beta factor (current gain), an on-chip stable voltage source is desired to maintain the collector current in the doubler. Thus, a transistor biased in the saturation region can be used to fix the base voltage and sustains the doubler in the pinch-off region. Under 5-dBm input drive, this balanced doubler demonstrates a measured conversion gain of 6.1 dB at 31 GHz. The fundamental rejection is better than 23 dB.

A -band High LO-to-RF Isolation Triple Cascode Mixer With Wide IF Bandwidth

A W-band triple cascode down conversion mixer using a 0.15- μm pseudomorphic high-electron mobility transistor process is proposed in this paper. Due to the utilization of modified bias topology, resistive mixing core, and IF low-pass filter, this circuit has a very wide IF bandwidth. Moreover, the triple cascode structure is used in this mixer for high local oscillator (LO)-to-RF isolation and compact chip area. The measured results illustrate that the mixer achieves 9-13-dB upper sideband conversion loss with dc-to-26-GHz IF bandwidth, and the LO-to-IF, LO-to-RF, and RF-to-IF isolation are 38, 42, and 40 dB, respectively with 5-dBm LO power at 86 GHz. When the LO power is 7 dBm at 96 GHz, the upper sideband conversion loss is 10-14 dB with dc-to-24-GHz IF bandwidth, and LO-to-IF, LO-to-RF, and RF-to-IF isolation are 29, 41.5, and 45 dB, respectively. The power consumption is 24 mW and chip area is 1 mm2.

Q-Band GaAs Bandpass Filter Designs for ALMA Band-1

We report on the design and experimental results of Q-band GaAs bandpass filters (BPFs) for the Atacama Large Millimeter/submillimeter Array (ALMA) band-1 receiver. The BPF is required to reject the lower side band from 15.3 to 29 GHz while retain minimum insertion loss across the passband of 31.3 to 45 GHz. In order to reduce the size and weight of receiver module effectively, on-chip BPF designs using the commercial GaAs process are proposed. The parallel-coupled BPF with quarter-wavelength resonators is adopted to achieve a wide fractional bandwidth of about 37%. In addition, the capacitive/inductive loaded coupled-line and the stepped-impedance resonator are used to largely reduce the filter size. Moreover, the cross-coupling effect is introduced to create transmission zeros, such that the required 25 dB stopband rejection below 29 GHz can be achieved. Specifically, two GaAs BPFs with sizes less than 1.24times0.8 mm2 are demonstrated. They will be applied to the multi-chip-module version of ALMA band-1 receiver prototype for further system evaluation and feasibility studies.

A Wide Tuning Range Voltage Controlled Oscillator Using Common-Base Configuration and Inductive Feedback

Usually the tuning range of voltage controlled oscillator (VCO) is much narrower than the possible resonant frequency range of the tank at different tuning voltages. In this letter we analyze the traditional common-base type VCO, give a simple but useful insight about the mechanism behind the topology, and verified the conclusions with a 2 mum heterojunction bipolar transistor (HBT) VCO. The results show that with the CB configuration, proper feedback inductor and wide tuning range varactor, the tuning range can be almost the same as the resonant frequency range of the tank at different tuning voltages. A wideband voltage controlled oscillator using a commercial 2 mum HBT technology is designed, fabricated and measured. The varactor with wide range of capacitance is used to achieve 53.33% measured tuning range from 9.46 to 16.34 GHz. The measured phase noise at 1 MHz offset is between -90 and -102 dBc/Hz. The total chip size is 1 mm2 including all testing pads, while the core area is 0.64 mm2. The VCO is suitable for wideband application such as in measurement equipment or astronomical exploring telescopes.

Q-band low noise amplifiers using a 0.15μm MHEMT process for broadband communication and radio astronomy applications

Two Q-band low noise amplifiers using a 0.15-μm InGaAs MHEMT process for broadband communication and radio astronomy applications are presented in this paper. Between 37 and 53 GHz, the LNA1 features a small signal gain of higher than 31 dB, a noise figure of better than 3.5 dB with a minimum noise figure of 2.8 dB at 44 GHz, and a gain-bandwidth product (GBP) of 679 GHz. Between 32 and 50 GHz, the LNA2 features a small signal gain of higher than 28 dB, a noise figure of better than 3.2 dB with a minimum noise figure of 2.6 dB at 44 GHz, and a GBP of 569 GHz. The chip sizes of the LNA1 and LNA2 are both 2 x 1 mm2. The LNAs demonstrate broad bandwidth, high gain, low noise figure, and compact chip size, and they will be further applied to a few broadband receivers for communications and radio astronomy applications. Moreover, this work demonstrates the highest GBP among all the reported Q-band LNAs.

A 30–50 GHz Wide Modulation Bandwidth Bidirectional BPSK Demodulator/ Modulator With Low LO Power

A 30-50 GHz wide modulation bandwidth bidirectional binary phase shift keying (BPSK) demodulator/modulator using a 2 mum standard GaAs HBT process is presented in this letter. A single balanced mixer with HBT PN-junction diodes is employed in the circuit design. With a local oscillator (LO) power of 0 dBm, this letter demonstrates a maximum conversion loss of 13 dB, a modulation bandwidth of wider than 3 GHz, and a LO-to-RF isolation of better than 45 dB. The BPSK demodulation or modulation can be performed at the same input/output ports of the circuit, and therefore it can be applied to millimeter-wave (MMW) gigabit bidirectional communication systems to further reduce the complexity of the transceivers.