Ming-Fong Lei

An analysis of miniaturized dual-mode bandpass filter structure using shunt-capacitance perturbation

A dual-mode bandpass ring filter using two pairs of shunt capacitances has been analyzed and designed. The size of the ring resonator can be reduced significantly by increasing the shunt capacitances. Since the resonator size is not an integer multiple of operating frequency, harmonic suppression is easily achieved. Analysis shows that the two pairs of shunt capacitances independently control the even- and odd-mode resonant frequency of the ring resonator. Moreover, the shunt capacitance also allows easier biasing, making tunable filters using varactors realizable. Various configurations of dual-mode bandpass filters have been reported, and the advantages and disadvantages of each structure are discussed. Several filters of various capacitances have been designed and tested at 1.8 GHz, and show significant size reduction of over 67%. A varactor-tuned filter has also been designed, and demonstrated a measured tunable center frequency of 20%. This study is a solution to the miniaturization of ring filters, and allows performance tuning, making ring filters more attractive in monolithic microwave integrated circuits and system-on-chip applications.

Design and Analysis for a 60-GHz Low-Noise Amplifier With RF ESD Protection

An RF electrostatic discharge (ESD) protection for millimeter-wave (MMW) regime applied to a 60-GHz low-noise amplifier (LNA) in mixed-signal and RF purpose 0.13-mum CMOS technology is demonstrated in this paper. The measured results show that this chip achieves a small signal gain of 20.4 dB and a noise figure (NF) of 8.7 dB at 60 GHz with 65-mW dc power consumption. Without ESD protection, the LNA exhibits a gain of 20.2 dB and an NF of 7.2 dB at 60 GHz. This ESD protection using an impedance isolation method to minimize the RF performance degradation sustains 6.5-kV voltage level of the human body model on the diode and 1.5 kV on the core circuit, which is much higher than that without ESD protection (< 350 V). To our knowledge, this is the first CMOS LNA with RF ESD protection in the MMW regime and has the highest operation frequency reported to date.

Design and Analysis of Stacked Power Amplifier in Series-Input and Series-Output Configuration

The stacked-device power-combining technique is a proven method to increase the output power and load impedance of a power amplifier (PA) simultaneously. The series-input configuration is physically realizable for multicell stacked device configuration in monolithic circuits. The series-input and series-output stack configuration is rigorously analyzed and proven to increase both the input impedance and output impedance simultaneously, easing the matching circuit designs in high PAs. The effects of asymmetry of the input feed and amplifier cells due to distributed effects and process variation on the performance of the stack amplifier are discussed. A four-cell HBT amplifier operating at 5-6 GHz is demonstrated to validate the circuit concept.

FET-integrated CPW and the application in filter synthesis design method on traveling-wave switch above 100 GHz

A new transmission-line concept, called the field-effect transistor (FET)-integrated coplanar waveguide (CPW), is proposed. This concept treats the passive two-finger FET as CPW and, thus, the scaling rule is more accurate than the previous model, especially in high frequency. The extraction approach of the parameters of the FET-integrated CPW is also included. With this concept, the design procedure of traveling-wave switches can be equivalent to a filter synthesis problem. Based on this design procedure, a single-pole single-throw and a single-pole double-throw traveling-wave switch have been realized and measured using 0.15-/spl mu/m high-linearity AlGaAs/InGaAs/GaAs pseudomorphic high electron-mobility transistors. Finally, the frequency limitation of the traveling-wave switches is also discussed. The results show the FET-integrated CPW is the most efficient way to overcome the frequency limitations of traveling-wave switches, achieving operation frequency to 135 GHz, the highest frequency reported to date.

Design and analysis of a miniature W-band MMIC subharmonically pumped resistive mixer

A W-band monolithic sub-harmonically pumped (SHP) resistive mixer was designed and fabricated using a standard 0.15/spl mu/m PHEMT process. A nonlinear model featuring modified drain-current characteristics was developed and used in circuit simulation. A small chip size of 1.5 /spl times/ 1.0 mm/sup 2/ was achieved by using a transformer as a LO balun. Measured results of this circuit showed 14-18 dB conversion losses from 75 to 88 GHz, and agree well with simulation. Analysis on circuit imbalance shows that the phase imbalance of the balun is the dominant factor on LO isolation, and the conversion loss is quite robust to all circuit imbalances.

A 4–41 GHz Singly Balanced Distributed Mixer Using GaAs pHEMT Technology

A broadband singly balanced distributed mixer is developed using a 0.15-mum GaAs pHEMT foundry process. It is the first time that the charge-injection approach is applied to a distributed mixer. With the advantage of charge-injection, the mixer achieves a high conversion gain with low dc consumption. The fabricated distributed mixer with an integrated broadband transformer has a compact chip size of 2mmtimes1mm. Measurement results show that the mixer achieves a conversion gain of better than 3.5dB over a broadband frequency from 4-41GHz, with a relatively low dc power consumption of 100mW

DC-to-135 GHz and 15-to-135 GHz SPDT traveling wave switches using FET-integrated CPW line structure

High operation frequency SPST and SPDT switches based on commercial 0.15-/spl mu/m GaAs pHEMT are developed. A novel integrated CPW line structure, which integrates the device, signal line and ground into the CPW line structure, is proposed. By using this structure, the limitation of the traveling wave switch caused by the parasitic inductance between the device to signal and ground in the conventional microstrip line designs can be removed. From the measurement results, high operation frequency of 135 GHz is achieved. The SPST switch achieves less then 5 dB insertion loss from DC to 135 GHz. The SPDT switch achieves less than 6 dB insertion loss from 15 GHz to 135 GHz. This switch has the highest operation frequency among the reported traveling wave switches.

A low noise bulk-coupled colpitts CMOS quadrature VCO

This paper proposes a quadrature voltage-controlled oscillator (QVCO) using 0.18-mum 1P6M standard CMOS process. The QVCO is realized by combining two differential oscillators via the bulk terminals. Using this approach, we can reduce the power dissipation and remove the noise from the additional coupling transistors compared with conventional QVCOs. To improve the phase noise, the oscillator is composed of Colpitts topology for lower phase noise than its cross-coupled counterpart. Moreover, the Colpitts oscillator adopts only PMOS to achieve a better phase noise performance because PMOS has less 1/f noise than NMOS. The VCO operates from 4.9 to 5.5 GHz with more than 11% tuning range. The measured phase noise at 600-kHz offset is -117 dBc/Hz at 5.2 GHz. The QVCO dissipates 10.8 mW at 1.8 V and achieves a good FOM of 185 dB.

Implementation of Reduced-Size Dual-Mode Ring Filters in LTCC and MMIC Processes at Millimeter Wave Frequencies

Millimeter-wave applications of the reduced-size dual-mode ring filters are investigated in this paper using low-temperature co-fired ceramics (LTCC) and MMIC processes. The LTCC version of the reduced-size ring filters is designed at 28 GHz, and the monolithic version is fabricated on 4-mil GaAs substrate. Insertion losses of under 3 dB are achieved. Coupling due to extensive size reductions and process variations have various effects of the filter performance, and are observed in the experiments. These results demonstrate the performance of reduced-size ring filters in millimeter-wave applications, and also suggest the possibility of system-on-package (SOP) and system-on-chip (SOC) of this miniature filter structure

A broadband medium power amplifier for millimeter-wave applications

A power amplifier using 0.15-/spl mu/m GaAs pHEMT technology is presented. This amplifier combines two conventional distributed amplifiers to achieve wide bandwidth, high gain and moderate output power. The measured small signal gain is 15.3 /spl plusmn/ 1 dB from 4 to 37 GHz with a chip size of 2 /spl times/ 1.5 mm/sup 2/. The output saturated power is 20.6-23.3 dBm from 4 to 37 GHz. The wide bandwidth and large output power makes it useful in many microwave and millimeter wave applications, such as broadband amplifiers in microwave equipment, and ultra-wide-band signal amplification.