Abstract: A wideband microstrip leaky-wave antenna comprising a substrate with a cavity, a microstrip line located on a first surface of the substrate and a conductive plate located on a second surface of substrate opposite to the first surface. Using the cavity between the microstrip line and the conductive plate can reduce the effective dielectric constant of the substrate and further increase the bandwidth of the antenna. In addition, the microstrip line also can be located in the cavity. In this case, there is no dielectric material between the microstrip line and the conductive plate.

Abstract: The present invention relates to a chip antenna which comprises a substrate, a feeding pad, a feeding conductor, a matching unit, and a meandering conductor. The substrate formed with a dielectric material. By varying the length of the meandering conductor, the central frequency of the chip antenna can be properly obtained and controlled. The matching unit, which is formed by joining a matching conductor with a ground plate, uses the short-circuit function of the matching conductor to obtain the desired bandwidth. In this way, the chip antenna is well suited for applications in wireless communication systems, including personal mobile communication networks and equipment.

Abstract: In a stripline configuration, a laminated lowpass filter circuit includes first through fifth dielectric substrates arranged in that order in a stack, first and second groundplane conductor layers disposed on the outer surfaces of the stack, and a shielding conductor layer formed on the third dielectric layer. First and second side electrodes are formed on sides of the stack. A stripline providing an inductive element is formed on the fourth dielectric layer, and first and second conductor plates providing capacitive elements are formed on the first and second dielectric layers. The terminal of the first conductor plate and a first end of the stripline are connected to the first side electrode. A terminal of the second conductor plate and a second end of the stripline are connected to the second side electrode. The first and second side electrodes constitute input and output terminals of the laminated lowpass filter circuit.

Abstract: A balun circuit includes a dielectric substrate having planar opposing surfaces: a groundplane conductor layer disposed on a first opposing surface; an interlayer conductor layer disposed on a second opposing surface and including first and second electrically isolated conducting strips, with a balance point gap between first ends thereof, and second ends thereof being short-circuited; an interlayer dielectric layer having substantially planar opposing surfaces, with a first opposing surface thereof being disposed over the interlayer conductor layer; and a top conductor layer disposed over a second opposing surface of the interlayer dielectric layer and including a third conducting strip overlying the first and second conducting strips, one end of the third conducting strip providing an unbalanced port terminal and another end of the third conducting strip being open-circuited.

Abstract: The inventive bandstop filter is suitable for use in a multi-layer ceramic (MLC) structure. Specifically, the filter is a semi-lumped type, formed by lumped capacitors and distributed transmission lines. Preferably, transmission lines are used as equivalent inductors, instead of as J, K inverters or resonators. The bandstop filter preferably has attenuation poles very close to lower passband edge, which results in a very sharp rejection near the stopband. The inventive filter may be utilized as a transmitter-end filter in, e.g., duplexer applications or for miniaturized applications, such as portable communications.

Abstract: The inventive bandpass filter is suitable for use in a multi-layer ceramic (MLC) structure. Specifically, the filter is a semi-lumped type, formed by lumped capacitors and distributed transmission lines. Preferably, shorted transmission lines are used as equivalent inductors, which are connected with high value lumped capacitors to form resonators. Accordingly, the size of the resonators can be much smaller than 1/4 of the signal wavelength. The bandpass filter preferably has attenuation poles very close to lower passband edge, which results in a very sharp rejection near the stopband. The inventive filter may be utilized as a receiver-end filter in, e.g., duplexer applications or for miniaturized applications, such as portable communications.