Motorola Corporation

3d Glass Solutions, Inc.

Reddy R Vangala

Truc G Hoang

Jeb H Flemming

Michael A Newell

Frederick L Sassin

Constantine Vlahos

Michael Kip Waldo

David John Boughton

The present invention includes a method of a low cost, reliable novel broadband inductor that can be used with a capacitor to form a broadband filter.

Broadband induction

A dual band filter network for a radio communication apparatus is provided. The network has an antenna (212) for receiving and transmitting signals from a first frequency band and a second frequency band. The network has a first duplex pair (202) including a first transmit filter (204) including a first passband and stopband. The first duplex pair (202) also includes a second receive filter (206). The first filter (204) presents a consistent phase in the second passband due to the wide frequency separation between the first filter (204) and the second filter (206). The network has a second duplex pair (202') with similar characteristics as the first duplex pair (202). The network also has a switching circuitry (210) controlled by a switch control voltage (214) for selecting the appropriate filter circuitry. The network can be provided in a small sized, low cost package that also offers improved insertion loss performance.

Dual-band filter network

An improved shield and ceramic filter. The shield includes (i) an upright portion (16) comprising a conductive material, (ii) a chamfered portion (22) disposed atop the upright portion (16), (iii) a horizontal portion (18) disposed on a distal portion of the chamfered portion (22) and (iv) one or more openings (20) disposed on the chamfered portion (22). The improved shield (12) desirably but not essentially further includes at least one slot (26) cut into a basal section of the upright portion (16). The at least one slot (26) allows a microstrip transmission line to pass under a portion of the shield (12).

Shield and ceramic filter

A ceramic filter with a coplanar shield which has: a filter body (302) comprising a block of dielectric material having top (304), bottom (306) and side surfaces (308,310,312,314), and having a plurality of metallized through holes (316) extending from the top (304) to the bottom (306) surfaces defining resonators; a metallization layer substantially coating the bottom (306) and the side surfaces (306,310,312,314), and the top surface (304) having a metallized pattern thereon defining a top pattern; input-output pads (318); and a conductive shield (322) having standoff legs (324) which maintain the conductive shield at a predetermined height above the top pattern of the filter body, the standoff legs (324) are connected to a portion of the top pattern on the top surface of the filter at a desired distance from the side surface having the input-output pads.

Ceramic filter with a coplanar shield

A high frequency ceramic waveguide bandpass filter (100) having: two or more waveguide resonators (102) stacked vertically, each adjacent waveguide resonator is coupled with a shunt capacitance, and includes: a plate of dielectric material having a top planar surface (108), a bottom planar surface (110), and four side surfaces (112, 114, 116 and 118); a metallized receptacle (120) on the planar surface (108) and the bottom planar surface (110), the metallized receptacles (120) defining capacitive probes; a metallization layer on substantially all the surfaces of the resonators (102) with the exception of an unmetallized area (124, 126) surrounding the capacitive probes; and the resonators (102) having a conductive interface adapted to electrically connect to an adjacent resonator.

Ceramic waveguide filter with stacked resonators having capacitive

A ceramic filter (100) with a transmission zero is disclosed. The filter (100) includes a block of dielectric material having top (102), bottom (104), and side surfaces (106, 108, 110 and 112), and having two or more metallized through-holes extending from the top to the bottom surfaces (102, 104), defining approximately half wave long resonators. The surfaces are substantially covered with a conductive material defining a metallized layer, with the exception that the top surface (102) is substantially uncoated, and with the additional exception that the bottom surface (104) is also substantially uncoated defining a filter with an open circuit at both ends. The filter (100) also has an input and an output (118, 120) and a mechanism or slot for electrically isolating successive resonators, extending about halfway between the top (102) and bottom surface (104). A filter constructed as detailed above, can have a higher Q value and lower insertion loss.

Half wave ceramic filter with open circuit at both ends

A method of tuning a duplex filter (500). First, the center frequency of at least one filter of a duplex filter (10) is measured (502). Next, the difference between the measured center frequency and a desired center frequency is determined (504). And, third the duplex filter is tuned (506) by selectively removing a substantially planar layer of dielectric material for a top surface (14) of the filter (10), whereby the frequency characteristics are modified.

Method of tuning a ceramic duplex filter using an averaging step

A ceramic duplex filter is provided. The duplex filter (10) has a filter body (12) of a dielectric material, and has a top (14), bottom (16) and side surfaces (18, 20, 22, and 24) with through-holes extending from the top (14) to the bottom surface (16). Receptacles are positioned adjacent to the top surface (14) with a conductive material therein. The surfaces (16, 18, 20, 22 and 24) are substantially covered with a conductive material defining a metallized layer (25), with the exception that the top surface (14) is substantially unmetallized. The receptacles include a conductive layer of material to define a certain capacitance. And, coupling devices (94, 96 and 98) for coupling signals into and out of the duplex filter (10) are provided. Shunt, series and coupling capacitors are strategically positioned adjacent to the top surface (14), which help to facilitate tuning of the filter.

Ceramic duplex filter

A ceramic bandpass filter (10) that has transmission zeroes above the passband is accomplished without using the top patterning by a block structure that includes a localized mesa (26) formed at the top end of the block that provides increased capacitive coupling between the open circuits and the resonators (30, 32, and 34). This increased top end capacitance provided by the mesa (26) can provide high end or high side transmission zeroes to the characteristic transfer function of the filter.

Block filter having high-side passband transfer function zeroes

A dielectric block filter having a self aligning, top and shield is provided. Recesses are formed in at least one side of the block, which recess is dimensioned to accept a mating tab or side of a shield that substantially encloses the top end of the filter. The recess in the block in combination with the appropriately shaped tab produces the overall height of the filter and simplifies manufacturing by eliminating the need to hold or affix the shield to otherwise smooth sides of the block.

Growing community of inventors

Albuquerque, NM, United States of America

Reddy R Vangala