Abstract: A cross-coupled bandpass filter includes first, second, third and fourth resonators such that magnetic couplings are generated between the first and second resonators, between the third and fourth resonators and between the first and fourth resonators, a capacitive coupling is generated between the second and third resonators, and the magnetic coupling between the first and fourth resonators has a polarity opposite to that of the capacitive coupling between the second and third resonators, thereby generating two transmission zeros in a transmission rejection band.

Abstract: A balanced-to-unbalanced converter (balun) is provided, including: a converting circuit having a first processing circuit including a first inductor and a first capacitor connected in series, a second processing circuit including a second capacitor and a second inductor connected in series, the second capacitor being electrically connected to the first inductor, and two balanced output ends connected to the first processing circuit and the second processing circuit, respectively; and a preprocessing circuit connected to the converting circuit and including an unbalanced input end for converting real impedance at the unbalanced input end into complex impedance at the balanced output ends. Accordingly, the balun satisfies the need of the wireless communication chips by providing differential signals with complex impedance.

Abstract: A circuit structure is provided, which includes: a first circuit portion having at least a capacitor; a first dielectric portion combined with the first circuit portion; a second circuit portion electrically connected to the first circuit portion and having at least an inductor; and a second dielectric portion combined with the second circuit portion, wherein the first dielectric portion has a greater dielectric constant than the second dielectric portion, thereby increasing the capacitance value and density and causing the inductor to have a high enough Q value.

Abstract: A cross-coupled bandpass filter includes first, second and third resonators such that a positive mutual inductance is generated between the first and third resonators and mutual inductance generated between the first and second resonators and mutual inductance generated between the second and third resonators have the same polarity, thereby generating a transmission zero in a high frequency rejection band.

Abstract: A multi bandwidth balun is provided, including a main signal port, a main inductor electrically connected to the main signal port, a first inductor inducted mutually with the main inductor to constitute a first inductor of a first conversion circuit, a first capacitor module connected in parallel to the first conversion circuit, two first signal ports electrically connected to the first capacitor module, a first main capacitor electrically connected to the first signal port and the first capacitor module therebetween, a second inductor inducted mutually with the main inductor to constitute a second inductor of a second conversion circuit, a second capacitor module connected in parallel to the second conversion circuit, two second signal ports electrically connected to the second capacitor module, and a second main capacitor electrically connected to the second signal port and the second capacitor module therebetween.

Abstract: A duplexer is provided, which includes a first, a second and a third signal ports; a first filter and a second filter. The first filter has first, second, and third resonant circuits that have first, second and third inductors, respectively. The first, second and third inductors are mutually inductive. The first and third resonant circuits are electrically connected to the first and second signal ports, respectively. The second filter has fourth, fifth and sixth resonant circuits that have fourth, fifth and sixth inductors, respectively. The fourth resonant circuit is connected in series with the first resonant circuit. The fifth inductor and the fourth inductor are mutually inductive. The sixth resonant circuit is electrically connected to the third signal port. The second filter further has a main capacitor connected in series with the fifth and sixth resonant circuits respectively and located therebetween.

Abstract: A testing method is provided, including providing a testing apparatus including a carrier member and a testing element, the carrier member comprising a first surface, a second surface opposing the first surface, and an elastic conductive area defined on the first surface; disposing an object-to-be-tested on the elastic conductive area; electrically connecting the testing element to the object-to-be-tested and the carrier member, to form an electric loop among the carrier member, the object-to-be-tested and the testing element. Through the design of the elastic conductive area, the object-to-be-tested can be secured with a small pressure applied thereto, and is prevented from being cracked.

Abstract: A semiconductor substrate is disclosed. The semiconductor substrate includes a substrate body having at least an opening formed on a surface thereof, wherein the surface of the substrate body and a wall of the opening are made of an insulating material; and a circuit layer formed on the surface of the substrate body, wherein the circuit layer covers an end of the opening and is electrically insulated from the opening. The opening facilitates to increase the thickness of the insulating structure between the circuit layer and the substrate body of a silicon material to prevent signal degradation when high frequency signals are applied to the circuit layer.

Abstract: A balanced-to-unbalanced converter (balun) is provided, including: a converting circuit having a first processing circuit including a first inductor and a first capacitor connected in series, a second processing circuit including a second capacitor and a second inductor connected in series, the second capacitor being electrically connected to the first inductor, and two balanced output ends connected to the first processing circuit and the second processing circuit, respectively; and a preprocessing circuit connected to the converting circuit and including an unbalanced input end for converting real impedance at the unbalanced input end into complex impedance at the balanced output ends. Accordingly, the balun satisfies the need of the wireless communication chips by providing differential signals with complex impedance.

Abstract: A cross-coupled bandpass filter includes first, second, third and fourth resonators such that magnetic couplings are generated between the first and second resonators, between the third and fourth resonators and between the first and fourth resonators, a capacitive coupling is generated between the second and third resonators, and the magnetic coupling between the first and fourth resonators has a polarity opposite to that of the capacitive coupling between the second and third resonators, thereby generating two transmission zeros in a transmission rejection band.

Abstract: A cross-coupled bandpass filter includes first, second and third resonators such that a positive mutual inductance is generated between the first and third resonators and mutual inductance generated between the first and second resonators and mutual inductance generated between the second and third resonators have the same polarity, thereby generating a transmission zero in a high frequency rejection band.