Abstract: An LC-type dielectric filter includes a plurality of substrate layers which are arranged in a stack and laminated to form a multi-layer substrate. Strip line resonators are provided on some of the substrate layers. The filter has a plurality of terminals, which are connected to resonators. The terminals are also capacitively or inductively coupled to each other. At least one grounding layer is included in the stack for electrically isolating the resonators. Coupling between the resonators can be obtained by forming a plurality of resonators close to one another on the same substrate layer. Further, a duplexer can be made from filters of this type. The duplexer may include a matching circuit and a power amplifier for RF transmission.

Abstract: A compact, high performance strip line filter which may be made thinner than a dielectric filter having comparable performance characteristics. The strip line filter includes a rectangular box-shaped, dielectric block having parallel grooves, formed in a front face with a predetermined spacing therebetween, the grooves extending from a top face to a bottom face of the block. A thin film outer conductive layer covers the side faces, the back face, and the bottom face. Resonator conductors, each formed of a thin film of conductive material, cover the respective surfaces of the grooves and are connected to the outer conductor. According to a further aspect, a substrate, with capacitor formed thereon, opposes a face of the dielectric block to provide capacitive coupling. The capacitors may be arranged to provide attenuation poles at finite frequencies. In accordance with another aspect, such strip line filters are used as the transmitting and receiving filters of a duplexer filter.

Abstract: A branching filter in which an input/output port, a first dielectric filter for use in transmission and a second dielectric filter for use in reception are coupled with each other through a branching filter circuit. The branching filter circuit includes a first line provided between the input/output port and an input port of the second dielectric filter, a second line provided between the input/output port and an output port of the first dielectric filter, and a third line provided between the input/output port and the ground. In the filter, conductor lines for use in connection between ports are used for the first and second lines.

Abstract: A dielectric filter includes a unitary dielectric block formed of a uniform, single dielectric material and having electrically conductive metallized patterns formed on front, rear and lateral walls, and on an outer bottom surface thereof. A plurality of coaxial dielectric resonators each including an open end and a central conductor are longitudinally arranged along the center of a top surface of the block and are spaced apart a predetermined distance. Frequency adjusting patterns are formed on the top surface of the block, each frequency adjusting pattern extending around an open end of a respective one of the resonators. Coupling amount adjusting patterns are also disposed on the top surface of the block, each connected to the front and rear walls and disposed between adjacent ones of the frequency adjusting patterns. At least one additional coupling amount adjusting pattern is disposed on the top surface of the block.

Abstract: A dielectric filter includes a homogeneous monolithic block of dielectric material having a plurality of parallel extending dielectric resonators formed therein. A plurality of first electrodes extend alond the top surface of the monolithic block, each encompassing an opening in the monolithic block defined by a corresponding one of the plurality of dielectric resonators. Either the distance between adjacent dielectric resonators or the configuration of the first electrodes is established to cause an overcoupling based on the coupling impedance, thereby tuning an attenuation pole of the dielectric filter to a finite frequency. Additionally, second electrodes are provided along the top surface of the monolithic block extending between and spaced from the first electrodes and connected to a ground electrode.

Abstract: An LC-type dielectric filter which includes strip lines on a dielectric plate forming distributed constant type resonators. The strip lines and other elements of the filter, such as coupling capacitances are plated onto the dielectric plate as printed circuits to realize a small, high-Q dielectric filter which is suitable for mass-production.

Abstract: A microstrip line type resonator includes a rectangular parallelapiped dielectric plate, and a conductive microstrip line disposed on a top surface of the dielectric plate. The microstrip line has opposite ends respectively spaced from front and rear edges of the dielectric plate. The resonator further includes a first grounding layer disposed on an entirety of the bottom surface of the dielectric plate, and a second grounding layer disposed an entirety of the front, rear and side surfaces of the dielectric plate. The first grounding layer is electrically connected to the second grounding layer at the edges of the bottom surface of the dielectric plate. The microstrip line type resonator is a 1/2 wavelength resonator.

Abstract: A circuit such as a duplexer which isolates a first and second frequency signals respectively directed to and from an antenna terminal. A transmitter filter has a output terminal connected to a connecting point through a first inductor. A receiver filter has an input terminal connected to the connecting point. The connecting point is connected to the antenna terminal, and to ground through a second inductor. In a modified circuit the output terminal of the transmitter filter and the input terminal of the receiver filter are respectively connected to the connecting point through first and second capacitors. In the preferred embodiments the transmitter filter and the receiver filter are mounted to one side of a dielectric plate and the inductor and/or capacitors are formed by electrically conductive step lines and a capacitance patterns formed on the opposite side of the dielectric plate.

Abstract: An isolating circuit, which isolates a first frequency signal in a first frequency range and a second frequency signal in a second frequency range which is higher than the first frequency range, has as antenna terminal, a first filter and a second filter. The first filter, having a first input terminal and a first output terminal, receives a first input signal including the first frequency signal at the first input terminal and attenuates first frequency component of the first input signal below the first frequency range at a first attenuation rate and second frequency components of the first input signal above the first frequency range at a second attenuation rate. One of the first input and output terminals of the first filter is coupled to the antenna terminal. The first filter further has a first setting terminal setting the first attenuation rate and the second attenuation rate so that the second attenuation rate is greater than the first attenuation rate.

Abstract: A dielectric filter with an attenuation pole having sharp attenuation characteristics. The dielectric block employed in the present dielectric includes a dielectric block single-block formed of TiO.sub.2 or BaO, for example. The dielectric block of this type has a plurality of resonators extending from a top surface toward a bottom surface thereof, a plurality of adjusting patterns provided over the top surface thereof, an outer conductor formed by side surfaces and the bottom surface thereof, input and output electrodes, wherein the adjusting patterns, the outer conductor, input and output electrodes maybe plated, for example, by silver, and an insulated cable which may have one end connected to the outer conductor and another end connected to the output electrode is disposed over the plurality of resonators so as to be coupled thereto.

Abstract: A microwave filter comprising a rectangular ceramics block (30) having a plurality of elongated parallel holes (31-36) extending from the top surface to the bottom surface thereof. The holes are plated with conductive layers (37, 38), and flat conductive areas (39-44) coupled with the layers (37, 38) spatially disposed on the top surface of the dielectric block (30) surround opening ends of the holes (31-36). An input terminal and an output terminal are provided adjacent to the conductive areas (39, 44) at both the extreme sides of the dielectric block (30).

Abstract: In a band division type equalizer having a plurality of equalizer sections, the adjustment of each of the equalizer sections is accomplished through measurement of characteristics of a transmission means to be equalized and calculation of the difference of the measured characteristics and the desired characteristics. Since all of the equalizer sections are adjusted at the same time according to the result of the calculation, the adjustment does not suffer from interaction among the sections. An adjustable variable, for instance, a variable resistor for each section is mounted in a single setting unit separable from the rest of the equalizer circuit. Thus, after completely adjusting the setting unit, the setting unit is connected to the rest of the equalizer sections, and then the desired delay characteristic can be obtained. The equalizer section is for instance a Moschytz type delay circuit.