Yunqiu Wu

A New Shorted Microstrip Method to Determine the Complex Permeability of Thin Films

A new method is proposed to determine the complex permeability of ferromagnetic thin films from 100 MHz to 15 GHz. In this method, shorted microstrip transmission-line perturbation combined with the conformal mapping method is used. In contrast with previous methods to measure the thin films deposited on rigid substrates, this method neither requires any reference sample for calibration, nor requires the additional measurement to determine saturation magnetization. To assess the validity of this new method, three samples with different thicknesses are measured; comparisons are performed between the theoretical and experimental results, and the repeatability of this method is studied by measuring the samples five times. The results show that the complex permeability of ferromagnetic thin films can be measured within 10% errors.

A Broadband and Equivalent-Circuit Model for Millimeter-Wave On-Chip M:N Six-Port Transformers and Baluns

A new equivalent-circuit model and parameter-extraction method for six-port M:N on-chip transformers and baluns are presented in this paper. All of the elements in the proposed model are extracted directly by S-parameters based on full-wave electromagnetic (EM) simulations. Series branches in the model are used to capture the characteristics of the primary and secondary windings. The shunt impedance networks on the terminals represent the substrate loss. The magnetic coupling effects of windings are denoted by six mutual inductances. The electrical coupling effects are represented by mutual capacitances. In this paper, we have developed a parameter-extraction methodology for mutual inductances of six-port transformers. The proposed model and parameters extraction methodology are verified with a number of six-port transformers with different turn ratio by measurements and full-wave EM simulations. The proposed model shows good agreement with measured data over a wide frequency band.

A Large-Signal Statistical Model and Yield Estimation of GaN HEMTs Based on Response Surface Methodology

A novel nonlinear large-signal equivalent circuit statistical model of GaN HEMTs based on response surface methodology (RSM) is proposed in this letter. Thirty-four GaN HEMTs from 10 batches are measured and all the parameters in the large-signal equivalent circuit model are extracted by an in-house parameters extraction program. We choose the four most sensitive parameters of the drain-source current model and the gate charge model. The statistical method is modeled by using response surface methodology to change the range of the four parameters. The statistical model is implemented in Agilent-ADS and three S-band GaN HEMT power amplifier are designed by using the established statistical model for validation. The results show that good accuracy has been achieved by comparing measured and simulated output power (Pout) and power added efficiency (PAE). This method is simple and accurate for GaN HEMT power amplifier design and yield estimation.

Flexible microwave filters on ultra thin Liquid Crystal Polymer substrate

In this paper, investigations about the applications of ultra thin Liquid Crystal Polymer (LCP) in flexible microwave filters are carried out. The LCP substrate of 50μm substrate thickness was offered as a double copper clad laminate with 18μm copper laminate thickness. First, a microstrip line are fabricated and measured to show the microwave transmission characterization at flat and bending condition. Then, for demonstration purpose, a X band band-pass filter and a stepped impedance low pass filter were designed and tested with overall LCP dimensions of 5.4 × 3.2 mm2 and 15.7×2 mm2,respectively. For the filters, good agreement between the simulated and measured S-parameters and compact sizes are obtained. The bending effects of the microstrip line and the band-pass filter are also measured and the measured data shows a very low susceptibility to the S-parameters due to bending behavior. The results show that ultrathin LCP substrate is a promising candidate for the miniaturization and flexibility applications in microwave devices.

A novel tri-band band-pass filter using combined simplified CRLH and right-handed SIRs

In this study, a novel tri-band band-pass filter using combined simplified composite right-/left-handed (CRLH) and right-handed (RH) stepped impedance resonators (SIR) is presented. This filter utilizes the zeroth order resonance of the SIRs in the CRLH region and RH resonance in the RH region to produce three different passbands. The proposed filter is simulated and measured, and measurement results match well with simulation ones. Good properties of low in-band insertion loss, good out-band rejection, and compact size have been achieved and verified, and it can be easily applied in the microwave circuits and wireless communication systems.

A Ku band 4-Element phased array transceiver in 180 nm CMOS

A Ku Band (15∼18 GHz) 4-Element (4 Transmitters/4 Receivers) fully differential phased array transceiver is designed and fabricated using a 180nm CMOS process. The proposed phased array integrated with T/R switches and SPI controller is based on an all-RF structure. TX and RX channels are placed side-by-side to improve integration density and isolation. Each channel consists of a 5-bit phase shifter and a 4-bit attenuator. The measured maximum gain is 21 dB for a TX channel and 10.8 dB for a RX channel. The minimum noise figure of RX with T/R switch is 9.9 dB. The input referred PidB of RX is −14.5 dBm at 16GHz, while the output referred PidB of transmitter is 10 dBm at 16 GHz. Additionally, the RMS phase error of phase shifter is less than 4o, and the RMS amplitude error of attenuator is less than 3.2 dB. A RX element draws 114 mA from a 1.8 V supply, while a TX element consumes 145 mA with a 3.3V supply. The chip occupies 4.5∗5mm2 area including pads.

A 54.4–90 GHz Low-Noise Amplifier in 65-nm CMOS

This paper proposes a transformer-based broadband low-noise amplifier (LNA) for millimeter-wave application. The proposed LNA has four common-source stages. Three transformers are used to connect the drains of the former transistors and the sources of the following transistors to boost the transconductances of the following transistors. Thus, the gain of the circuit is effectively increased. In addition, the noise figure (NF) is decreased because the noise contributions of the following stages are further suppressed by the application of the transformers. To enhance the gain bandwidth, the gate inductor in each inter-stage matching network is independently adjusted to separate the main poles of the four stages. The LNA is demonstrated using a commercial 65-nm CMOS process. According to the measurement results, a maximum gain of 17.7 GHz at 67 GHz and a 3-dB gain bandwidth of 35.6 GHz are achieved. The measured NF is 5.4–7.4 dB at 54–67 GHz. The tested input 1-dB gain compression point (IP

An improved equivalent circuit model based on the CMOS on-chip multiple coupled inductors from DC to millimeter-wave region

_{1\,\text {dB}}

The design of a high gain on-chip antenna for SoC application

) ranges from −15.4 to −11.7 dBm in the entire 3-dB gain bandwidth. With 1-V power supply, the LNA consumes 19-mA dc current. The chip size is only 0.37 mm2 with all pads.

Compact multi-band transversal bandpass filters with source–load coupling

In this paper, an improved equivalent circuit model of multiple coupled inductors is proposed, as well as the parameter extraction method. First, the characteristics of the on-chip inductors are analyzed. Then according to electromagnetic properties of multiple coupled inductors, the improved equivalent model, which considers more parasitic effects among inductors, as well as the parameter extraction method are presented. The measurement structures are fabricated by the 0.18μm and 90nm CMOS technologies. It will be shown that the simulated results of the model are in good agreement with the measured results from DC up to millimeter-wave range and the validation of the proposed model is verified.