City University of Hong Kong

Other

Shao Yong Zheng

Xin Yu Zhou

Derek Ho

Wing Shing Chan

Kwok Wa Leung

Yong Mei Pan

Peng Fei Hu

Haihong Zhu

Shi Chang Chen

A dual-band HP omnidirectional antenna includes an electrically small (ES) first omnidirectional loop antenna for a first band, and a second omnidirectional loop antenna for a second band. The first omnidirectional loop antenna and the second omnidirectional loop antenna are capable of operating independently in the first band and the second band. A loading effect of the second omnidirectional loop antenna adapted to suppress a higher-order mode of the first omnidirectional loop antenna.

Electrically small, planar, horizontally polarized dual-band omnidirectional antenna

A Doherty power amplifier having a main power amplification device and an auxiliary power amplification device arranged in parallel with the main power amplification device includes a load modulation circuit having a harmonic injection circuit connected with respective outputs of the main power amplification device and the auxiliary power amplification device. The harmonic injection circuit is arranged to provide a phase shift to simultaneously modulate transfer of second harmonic components generated at the main power amplification device to the auxiliary power amplification device and transfer of second harmonic components generated at the auxiliary power amplification device to the main power amplification device, when the main power amplification device and the auxiliary power amplification device are operated at saturation.

Wideband Doherty high efficiency power amplifier

The present invention relates to the field of sleeve type bottle openers, in particular to a sleeve type bottle opener suitable for bottle stoppers of different sizes. The sleeve type bottle opener comprises a cylindrical sleeve body and a bottle mouth guide part, wherein the bottle mouth guide part is arranged at a lower end of the sleeve body. According to the present invention, rigid claws fixed to rigid walls as well as elastic claws fixed to elastic walls are arranged on an inner wall of the sleeve type bottle opener; the diameter of an inscribed circle corresponding to the elastic claws can vary with the stretching of the elastic walls, so that the sleeve type bottle opener can be applied to bottle stoppers of different sizes.

Sleeve type bottle opener suitable for bottle stoppers of different sizes

A Doherty power amplifier includes a main device in a main amplifier circuit and an auxiliary device in an auxiliary amplifier circuit arranged in parallel with the main amplifier circuit. The Doherty power amplifier further includes a load modulation network including a first open-circuited transmission line connected to an output of the main device; a second open-circuited transmission line connected to an output of the auxiliary device; and an impedance transformation and phase compensation network connected with the output of the main device and the output of the auxiliary device for providing a combined output power. The first and second open-circuited transmission lines are arranged directly adjacent one another to form, during operation, a mutual coupling therebetween.

Growing community of inventors

Hong Kong, China

Shao Yong Zheng