National Taiwan University

Zuo-Min Tsai

Huei Wang

Shih-Fong Chao

Huie Wang

George D Vendelin

Sebastian Hoppner

Mei-Chao Yeh

A switchable bandpass filter includes a first stepped-impedance resonator, a second stepped-impedance resonator wirelessly coupled to the first stepped-impedance resonator, and a first diode connected to one end of the second stepped-impedance resonator.

Switchable bandpass filter having stepped-impedance resonators loaded with diodes

A differential signal driven direct-current voltage generating device is proposed, which is designed for use with a PLL (phase-locked loop) circuit or a DLL (delay-locked loop) circuit system for generating an output of a direct-current (DC) voltage in response to a pair of differential signals, such as phase-difference signals; and which is characterized by the utilization of a capacitor-switched voltage doubler for doubling the output voltage of a charge pump so that the doubled voltage can be used as a control voltage for a PLL-VCO (voltage-controlled oscillation) or a DLL-VCDL (voltage-controlled delay line) circuit for generation of an output oscillating signal with a wider frequency range.

Differential signal driven direct-current voltage generating device

A switched-capacitor charge pump device is proposed, which is designed for integration to a circuit system, such as a PLL (phase-locked loop) circuit system, for generation of an output direct-current (DC) voltage with a wide amplitude range; and which is characterized by the utilization of two switched-capacitor circuit units in addition to the output capacitor circuit and the utilization of an output voltage comparing circuit (such as a Schmitt trigger) for comparing the end-result output DC voltage against a half-amplitude drive voltage such that when the switched-capacitor circuit units are subjected to a charging-discharging action for voltage pump-up or pump down operations, the switched-capacitor circuit units are switched between a full-amplitude drive voltage and a half-amplitude drive voltage. This feature allows the invention to provide an output DC voltage with a wider amplitude range than prior art.

Switched-capacitor charge pump device for generation of output direct-current voltage with wide amplitude range

A unilateral feedback power amplifier utilizes new feedback techniques and devices to make the amplified high-frequency signal unilateral, let the output power, power gain and impedance matching simultaneously accomplish the optimal values, and enhance the stability of the system. In this feedback amplifier, a generalized multi-port feedback circuit is in shunt with the input terminal and the output terminal of the power transistor. This generalized multi-port feedback circuit receives an amplified high-frequency signal and eliminates the reverse admittance of the amplified high-frequency signal to let the admittance value of the output amplified high-frequency signal approach zero so as to be unilateral. Moreover, the generalized multi-port feedback power amplifier differs from the conventional power amplifier of cascaded architecture in that the ground terminal of the power transistor is directly connected to the system ground. Therefore, the heat-radiating problem of the power transistor can be greatly improved.

Unilateral feedback power amplifier and method for realizing the same

A single-pole-double-throw switch is provided, which is configured to be integrated with a bandpass filtering function and includes four quarter-wavelength transmission lines connected in series, five resonators connected in parallel to each other, and four transistors connected in parallel to four of the five resonators. When two of the four transistors are turned on and the others are turned off, the single-pole-double-throw switch is equivalent to a third-order quarter-wavelength short-circuited stub bandpass filter.

Single-pole-double-throw switch integrated with band pass filtering function

A power amplifier includes a first transformer, a first transistor, a first resistor, a second transformer, a second transistor, a second resistor, and a bias circuit. The first transformer drives the first transistor. The second transformer drives the second transistor. The first transformer is connected in series with the second transformer. The first transistor is connected in series with the second transistor. Therefore, the power amplifier has input impedance and output power both greater than those of a conventional power amplifier.

Power amplifier having input ends combined in series and output ends combined in series

A traveling-wave switch includes a FET-integrated Coplanar Waveguide (CPW) line structure. The FET-integrated CPW line structure incorporates a transistor, a signal line, and the ground, that can be used to eliminate the limitations imposed by the parasitic inductance of the prior art on the operation frequency of the switch. The signal line is connected directly to the drain of the transistor, eliminating the parasitic inductance caused by the connection wire between the signal line and the transistor. The source of the transistor is coupled directly to the ground of the coplanar waveguide line, thus eliminating the parasitic inductance between the transistor and ground, and raising the operation frequency of the switch.

Growing community of inventors

Taipei, Taiwan

Zuo-Min Tsai