Yatao Peng

Compact Dual-band Bandpass Filter Using Coupled Lines Multimode Resonator

A quad-mode resonator is proposed for novel design of dual-band bandpass filters (DBBPFs) with good selectivity and compact size. The symmetrical resonator consists of a pair of coupled line sections (CLSs) and a transmission line section (TLS). Odd-/even-mode method is used to clarify the mode characteristics. Four excited resonant modes are applied to produce two passbands. The frequency ratio range can be adjusted by the CLSs, and the bandwidths can be controlled by the TLS. After installing a pair of U-shape coupling arms, a DBBPF with five transmission zeros ( TZs) around the two passbands are designed and fabricated. The measured results are in good agreement with the simulated results, demonstrating that the proposed filter is feasible in practical use.

Modified Gysel Power Divider with Harmonic Supperssion Performance

This paper presents a modifled Gysel power divider (PD) with harmonic suppression performance by utilizing equivalent ƒ- shaped, T-shaped and ƒ-T-hybrid-shaped open stubs transmission line (TL) models. Explicit closed-form expressions for generating parameters of the equivalent TL models are derived based on the ABCD matrix analysis. The proposed PD not only features suppression at the hoped harmonic frequencies and ∞exible layout, but also maintains Gysel PDs high power handling advantage. For demonstration, the simulated and experimental results of three proposed PDs at 1GHz implemented on microstrip are given.

A Compact Tri-Band Passband Filter Based on Three Embedded Bending Stub Resonators

A microstrip tri-band bandpass fllter (BPF) based on three embedded bending stub resonators (EBSRs) is proposed in this paper. Three resonant paths that resonate at three difierent frequencies can achieve three passbands. The lumped circuit models of the proposed fllter are given for designing. The fllter is extremely compact, whose area is about 0:047‚g £ 0:12‚g. There are two transmission zeros located between the flrst two passbands and a transmission zero between the second and third passbands, which results in good selectivity. For demonstrating the proposed fllter structure, a fllter at 0.9/2.14/3.6GHz is designed and fabricated. The measured results are well agreed with simulated ones, which indicate the validity.

A Modified Microstrip Wilkinson Power Divider with High Order Harmonics Suppression

In this paper, a modifled Wilkinson power divider structure with three order harmonics suppression is presented. The quarter-wavelength microstrip lines in the traditional Wilkinson power divider (WPD) are replaced by two transmission line segments with ends connected (TTLWEC). The TTLWEC performs the functions of impedance transformation and three order harmonics suppression. The design equations are deduced by odd- and even-mode theory. An example of power divider operating at 1GHz is designed and fabricated based on the printed circuit board technology. The measured results of 3.13dB insert loss (IL) and 35dB return loss (RL) are obtained at the operating frequency, and the flrst, second and third harmonic harmonics suppressions are i38dB, i44dB and i39dB, respectively, which agree well with the simulated results and validate the availability of the proposed structure.

An Extended Topology of Parallel-Circuit Class-E Power Amplifier Using Transmission-Line Compensation

This paper presents a parallel-circuit Class-E amplifier that maintains it operating characteristics even when the output capacitance of the transistor is greater than the optimum shunt capacitance. The finite dc feed inductor in the parallel circuit topology is replaced by a transmission-line compensation circuit to eliminate the limitations on the operating frequency imposed by the output capacitance. Theoretical formulas for the circuit elements of the proposed network are derived in detail, and the analysis is validated by simulation and measurement. The measured maximum output power of 40.1 dBm, drain efficiency of 77.5%, and power-added efficiency of 70.8% were obtained at 2.8 GHz with a 29.4-dBm input power. These measurements show a similar or better level of efficiency and output power that is reported for other amplifiers at lower frequencies using the same transistor.

Analysis and Design of a Broadband SiGe HBT Image-Reject Mixer Integrating Quadrature Signal Generator

In this paper, a broadband upconversion image-reject mixer integrating a quadrature signal generator is presented. The polyphase networks (PPNs ) are used to convert the single-ended local-oscillator input signal to quadrature signals. A pair of inductors is added to traditional PPN to enhance the return loss performance, while optimizing the image-reject ratio. A common-emitter transconductance using the feedforward technique is applied to a quadrature active Gilbert mixer to obtain relative high linearity, and the optical solution for high-frequency applications is given and analyzed. An active differential to single totem-pole balun is applied as the output stage, which is well matched to load impedance and can provide medium output power. Measured results show excellent performance in the designed frequency from 400 MHz to 6 GHz.

A dual-mode dual-band bandpass filter using a tri-stubs loaded multimode resonator (TSLMR)

This paper presents a tri-stubs loaded multimode resonator (TSLMR) for designing dual-band bandpass filters. The TSLMR produces four spitting modes and the modal character is analyzed by using odd- and even-mode methods. A pair of even–odd modes is used to form the first passband, while another pair is used to produce the second passband. This resonator structure provides sufficient degrees of freedom to control the central frequencies and bandwidth of each passbands. Meanwhile, multi-transmission zeros are properly tuned for the rejections between the two passbands and in the upper stopband. A dual-band BPF operating at 1.57 and 3.5 GHz is designed and fabricated. Without a shorted structure and extra resonator, the measured filter shows good performance for both in band matching and outside rejections of the desired dual-passbands.

Design of inverse class-E amplifier with finite D.C. feed inductance

This paper reports on a design of inverse class-E amplifier with finite D.C. feed inductance. The finite D.C. feed inductance is resonated by the parallel capacitance at the fundamental frequency. The direct design equations required to determine the optimum operations are derived in detail. Comparing with the classic inverse class-E amplifier, numerical results show that improvements in minimizing size, cost, and complexity of the circuit can be obtained by the inverse class-E topology with finite D.C. feed inductance. Comparing with the sub-harmonic and parallel-circuit class-E amplifiers, the inverse class-E topology with finite D.C. feed offers advantages for MMIC realization. Theoretical analysis is validated by numerical simulation and measurement. Excellent agreement between theory and simulation results is achieved. Comparison between simulations and measurements of an experimental circuit validate the feasibility of the design. A measured output power of 40.01dBm, with a drain efficiency of 80.16% and power-added efficiency of 78.93% were obtained at 250MHz with a 22-dBm input power.

A novel automatic attenuator with ultra-fast response time

This paper presents a novel automatic attenuator with ultra-fast transient response time. The proposed automatic attenuator combines control generation and a digital attenuator together. The control generation chain consists of a RF envelope detector, voltage comparators and a logic circuit. The state of the digital attenuator is determined by the output control signals of the control generation chain. The chip is fabricated using HuaHong 0.18 um standard CMOS technology. Measured results are offered showing that the transient response time of the whole system is less than 10 ns in the ultra-wide operation frequency range of 1GHz∼10GHz.

A 400MHz to 4GHz image-reject up convert mixer integrated a broadband quadrature signal generator

In this paper, a broadband up convert image-reject mixer integrated the quadrature signal generator is presented. The RC polyphase network (PPN) is used to convert the single-end LO input signal to differential and quadrature signals. A pair of inductors are added to the traditional PPN to enhance the image rejection ratio (IRR). A linearity enhanced tranconductance cell is applied to the quadrature Gilbert mixer to obtain a relative high linearity. The active differential to single balun is applied as the output stage, and the output port is matched to 50Ω. The mixer is fabricated based on the SiGe HBT technology, measured results show the excellent performance in the designed frequency from 400MHz to 4GHz.