Motorola Corporation

Darioush Agahi-Kesheh

Robert Kenoun

Alexander Wayne Hietala

Gregory Redmond Black

Duane C Rabe

Richard S Kommrusch

Rong-Fong Huang

Raymond L Sokola

Zdravko M Zakman

Frederick L Sassin

David M DeMuro

A switch circuit for a cellular radiotelephone operable in a TDMA communication scheme. The switch circuit is disposed upon a plurality of tandemly-positioned ceramic substrates having transmission lines disposed upon one of the ceramic substrates. The switch circuit alternately connects transmitter circuitry to an antenna or receiver circuitry to the antenna, thereby alternately to permit transmission or reception of signals generated by, or received by the radiotelephone. Because circuits disposed upon ceramic materials are of low insertion losses, the switch circuit is advantageously utilized to form a portion of the radiotelephone.

Multi-ceramic layer switch circuit

A filter duplexer, such as a filter duplexer for a radio transceiver, of minimum dimensions is disclosed. First and second filter portions of the duplexer each include a plurality of transmission lines. Cross sections of the plurality of transmission lines of each filter portion are of at least two different geometries. The amount of coupling between adjacent ones of the resonators, as well as the loading capacitances of such resonators, is controlled by the relative geometric configuration of the adjacent ones of the resonators. Because the amount of coupling between the resonators and the loading capacitances of the resonators is determinative of the filter characteristics of the filter duplexer, desired filter characteristics may be effectuated by careful selection of the geometric configurations of the resonators of each filter portion.

Multi-passband dielectric filter construction having a filter portion

A dielectric filter having at least two adjacently-positioned resonators extended therethrough. The two adjacently-positioned resonators are of trapezoidal cross-sections to form thereby trapezoidal resonators. By suitable selection of the configurations of such resonators, the amount of coupling between such adjacent resonators may be controlled. For instance, a minor base side of the first trapezoidal resonator may be positioned adjacent to a corresponding minor base side of the adjacent trapezoidal resonator, or a major base side of the first trapezoidal resonator may be positioned adjacent to a major base side of the adjacent trapezoidal resonator, or a minor base side of the first trapezoidal resonator may be positioned adjacent to a major base side of the second trapezoidal resonator. Such electromagnetic coupling between the adjacent resonators is controlled by the relative configurations of such resonators rather than by increasing the spacings between such adjacent resonators.

Dielectric filter construction having resonators of trapezoidal

A filter assembly comprised of a dielectric filter and a shield positioned about the dielectric filter. The dielectric filter may be surface-mounted upon a circuit board and includes at least one notch formed to extend along a side face surface thereof. The shield is integrally formed of two sheets of an electromagnetic wave-absorptive material interconnected by a shoulder forming a right angle to fit about two sides of the dielectric filter. At least one projecting prong, corresponding in number and position with the at least one notch of the dielectric filter, extends beyond an end surface of one of the sheets of the shield to interfittingly engage with a corresponding notch formed on the filter. The shield is positioned about the dielectric filter prior to tuning of the filter, and openings are formed to extend through the shield to permit access to the dielectric filter to permit tuning thereof once the shield is positioned thereabout.

Dielectric filter and shield therefor

A dielectric filter construction having at least two resonating cavities extending longitudinally through a block of dielectric material. At least one of the resonating cavities is of a cross-sectional area which is elongated in a transverse direction, and at least one notch is formed to extend longitudinally along at least one of the surfaces of the block of dielectric material between adjacent ones of the resonating cavities. By appropriate selection of the amount of elongation of the cross-section of the resonating cavity, and the location and dimension of the notch formed along the surface of the block, the component values of the component elements comprising the filter may be selected over an increased range without altering the physical size of the filter.

Dielectric filter having adjacently-positioned resonators of dissimilar

A low pass filter circuit for a radiotelephone which filters harmonic, spectral components of a modulated signal generated by the radiotelephone. The filter circuit is comprised of inductors and capacitors wherein each inductor and each capacitor of the filter is comprised of a distributed-element portion and a discrete-element portion. The distributed element portions of each inductor and each capacitor of the filter attenuate higher-frequency, spectral components of a signal applied thereto. The discrete element components of each inductor and each capacitor of the filter attenuate lower-frequency, spectral components of the signal applied thereto.

Filter circuit for attenuating high frequency signals

A voltage controlled oscillator and buffer amplifier circuit (211) is disclosed. The circuit is in a stacked configuration, whereby, the current from the power supply (361) is used by the buffer amplifier circuit and reused by the VCO circuit. The VCO circuit includes two transistors (333, 325). The transistors are set-up in a mirrored configuration, so that one of the transistors (325) controls the bias current in the other transistor (333). Both of the transistors are integrated into a semiconductor circuit die (365), thus, matching the thermal characteristics of the transistors (333, 325) and improving control of the bias current. The die (365) is bonded to a ceramic substrate (601). The substrate (601) has connectivity paths for connecting components in the circuit die to components external to the circuit die. Some of the connectivity paths are made of a material and length to form passive circuit elements.

Oscillator with bias and buffer circuits formed in a die mounted with

A dielectric filter assembly and mounting therefor. The mounting bracket forms a support surface and includes integrally formed strip members for interconnecting electrodes formed upon a face surface of the dielectric filter and a circuit disposed upon an electrical circuit board. Once interconnected, reflow solder connections are formed between the strip members and the electrodes and the strip members and the circuit disposed upon the circuit board. The strip member is then severed from the mounting bracket to electrically isolate the electrode disposed upon the face surface of the dielectric filter, while maintaining the electrical connection between the electrodes formed upon the dielectric filter and the circuit disposed upon the circuit board.

Dielectric filter and mounting bracket assembly

A dielectric block filter construction having resonating cavities formed therein to form one half wave-wavelength resonators thereby. The resonating cavities span opposing side surfaces of the dielectric block forming the dielectric block filter to define openings at the opposing side surfaces. Outer surfaces of the dielectric block, including the opposing side surfaces having the openings defined thereat, are coated with an electrically-conductive material except for portions of one side surface of the dielectric block about peripheral surfaces of input and output couplers formed on the one surface. Because the opposing outer surfaces are coated with the electrically-conductive material, the opposing outer surfaces of the dielectric block are self-shielding to prevent propagation of electromagnetic radiation through openings defined by the resonating cavities of the dielectric block.

Half wave resonator dielectric filter construction having self-shielding

A ceramic filter includes a multiple zero bandstop filter function. The ceramic filter has a dielectric block with top and bottom surfaces and at least two holes, including a first hole and a second hole, extending from the top surface toward the bottom surface of the block. The block is selectively covered with a conductive material to provide a transmission line resonator for each of the two holes. The filter also includes an input electrode coupled to the dielectric means at a predetermined distance from the first hole, and an output electrode coupled to the dielectric means at a predetermined distance from the second hole. Finally, conductive plating, in the form of a transmission line, is contiguously disposed on the dielectric means adjacent the two holes and coupled thereto to provide a bandstop filter function with a zero represented at each hole.

Growing community of inventors

Buffalo Grove, IL, United States of America

Darioush Agahi-Kesheh