Microstrip filter

Claim 2

A microstrip filter comprising: N microstrip open circuited, half-wavelength hairpin resonators including a ground plane, a substrate disposed adjacent to, coextensive with and parallel to said ground plane and N hairpin shaped conductors disposed in series coupled relationship with each other on one surface of said substrate opposite said ground plane, where N is equal to an integer greater than one, each of said N conductors including a pair of parallel spaced limbs interconnected by a cross-arm, adjacent ones of said N conductors having an opposite orientation with respect to each other and adjacent ones of said limbs of adjacent ones of said N conductors being in spaced parallel relationship with respect to each other to provide said series coupled relationship; a microstrip input coupler including a first conductor disposed on said one surface of said substrate in spaced, parallel relationship with an adjacent one of said limbs of a first of said N conductors to provide a series coupled relationship between said first conductor and said adjacent one of said limbs of said first of said N conductors; a microstrip output coupler including a second conductor disposed on said one surface of said substrate in spaced, parallel relationship with an adjacent one of said limbs of a last of said N conductors to provide a series coupled relationship between said second conductor and said adjacent one of said limbs of said last of said N conductors; each of said N conductors and said first and second conductors being in alignment; metallic members coextensive with said ground plane and said substrate enclosing said one surface of said substrate and said first, second and N conductors to shield said hairpin resonators to increase the unloaded Q of said resonators with respect to the unloaded Q obtainable with unshielded hairpin resonators.

Claim 3

A filter according to claim 1, wherein each of said limbs and said cross-arm of each of said N conductors between said first and last of said N conductors have a width equal to a first given amount; the spacing between each of said limbs of each of said N conductors between said first and last of said N conductors is equal to said first given amount; said first conductor includes a first portion parallel to said adjacent one of said limbs of said first of said N conductors and a second portion perpendicular to said first portion, said first portion and a section of said second portion directly connected to said first portion each have a width equal to a second given amount less than said first given amount; said second conductor includes a third portion parallel to said adjacent one of said limbs of said last of said N conductors and a fourth portion perpendicular to said third portion, said third portion and a section of said fourth portion directly connected to said third portion each have a width equal to said second given amount; and said adjacent one of said limbs of each of said first and last of said N conductors and a section of said cross-arms directly connected to said adjacent one of said limbs of each of said first and last of said N conductors have a width equal to said second given amount, the other of said limbs of each of said first and last of said N conductors and the remainder of said cross-arms connected to said other of said limbs of each of said first and last of said N conductors have a width equal to said first given amount and the spacing between said adjacent one and said other of said limbs of each of said first and last of said N conductors is greater than said first given amount.

Claim 4

A filter according to claim 2, wherein the thickness of said substrate is equal to said first given amount.

Claim 5

A filter according to claim 3, wherein said substrate is composed of 99.5 percent alumina.

Claim 6

A filter according to claim 1, wherein said substrate and said ground plane is separated by a metal carrier employed to test and adjust said filter prior to providing a final assembly thereof, said testing and adjusting taking place at a point removed from said final assembly.

Claim 7

A microstrip filter comprising: N microstrip open circuited, half-wavelength hairpin resonators including a ground plane, a substrate disposed adjacent to, co-extensive with and parallel to said ground plane and N hairpin shaped conductors disposed in series coupled relationship with each other on one surface of said substrate opposite said ground plane, where N is equal to an integer greAter than one, each of said N conductors including a pair of parallel spaced limbs interconnected by a cross-arm, adjacent ones of said N conductors having an opposite orientation with respect to each other and adjacent ones of said limbs of adjacent ones of said N conductors being in spaced parallel relationship with respect to each other to provide said series coupled relationship; a microstrip input coupler including a first conductor disposed on said one surface of said substrate in spaced, parallel relationship with an adjacent one of said limbs of a first of said N conductors to provide a series coupled relationship between said first conductor and said adjacent one of said limbs of said first of said N conductors; and a microstrip output coupler including a second conductor disposed on said one surface of said substrate in spaced, parallel relationship with an adjacent one of said limbs of a last of said N conductors to provide a series coupled relationship between said second conductor and said adjacent one of said limbs of said last of said N conductors; each of said N conductors and said first and second conductors being in alignment; each of said limbs and said cross-arm of each of said N conductors between said first and last of said N conductors having a width equal to a first given amount; the spacing between each of said limbs of each of said N conductors between said first and last of said N conductors is equal to said first given amount; said first conductor including a first portion parallel to said adjacent one of said limbs of said first and said N conductors and a second portion perpendicular to said first portion, said first portion and a section of said second portion directly connected to said first portion each having a width equal to a second given amount less than said first given amount; said second conductor including a third portion parallel to said adjacent one of said limbs of said last of said N conductors and a fourth portion perpendicular to said third portion, said third portion and a section of said fourth portion directly connected to said third portion each having a width equal to said second given amount; and said adjacent one of said limbs of each of said first and last of said N conductors and a section of said cross-arms directly connected to said adjacent one of said limbs of each of said first and last of said N conductors having a width equal to said second given amount, the other of said limbs of each of said first and last of said N conductors and the remainder of said cross-arms connected to said other of said limbs of each of said first and last of said N conductors having a width equal to said first given amount and the spacing between said adjacent one and said other of said limbs of each of said first and last of said N conductors is greater than said first given amount.

Claim 8

A microstrip filter comprising: N microstrip open circuited, half-wavelength hairpin resonators including a ground plane, a substrate disposed adjacent to, co-extensive with and parallel to said ground plane and N hairpin shaped conductors disposed in series coupled relationship with each other on one surface of said substrate opposite said ground plane, where N is equal to an integer greAter than one, each of said N conductors including a pair of parallel spaced limbs interconnected by a cross-arm, adjacent ones of said N conductors having an opposite orientation with respect to each other and adjacent ones of said limbs of adjacent ones of said N conductors being in spaced parallel relationship with respect to each other to provide said series coupled relationship; a microstrip input coupler including a first conductor disposed on said one surface of said substrate in spaced, parallel relationship with an adjacent one of said limbs of a first of said N conductors to provide a series coupled relationship between said first conductor and said adjacent one of said limbs of said first of said N conductors; and a microstrip output coupler including a second conductor disposed on said one surface of said substrate in spaced, parallel relationship with an adjacent one of said limbs of a last of said N conductors to provide a series coupled relationship between said second conductor and said adjacent one of said limbs of said last of said N conductors; each of said N conductors and said first and second conductors being in alignment; each of said limbs and said cross-arm of each of said N conductors between said first and last of said N conductors having a width equal to a first given amount; the spacing between each of said limbs of each of said N conductors between said first and last of said N conductors is equal to said first given amount; said first conductor including a first portion parallel to said adjacent one of said limbs of said first and said N conductors and a second portion perpendicular to said first portion, said first portion and a section of said second portion directly connected to said first portion each having a width equal to a second given amount less than said first given amount; said second conductor including a third portion parallel to said adjacent one of said limbs of said last of said N conductors and a fourth portion perpendicular to said third portion, said third portion and a section of said fourth portion directly connected to said third portion each having a width equal to said second given amount; and said adjacent one of said limbs of each of said first and last of said N conductors and a section of said cross-arms directly connected to said adjacent one of said limbs of each of said first and last of said N conductors having a width equal to said second given amount, the other of said limbs of each of said first and last of said N conductors and the remainder of said cross-arms connected to said other of said limbs of each of said first and last of said N conductors having a width equal to said first given amount and the spacing between said adjacent one and said other of said limbs of each of said first and last of said N conductors is greater than said first given amount.

Claim 9

A filter according to claim 6, wherein the thickness of said substrate is equal to said first given amount.

Claim 10

A filter according to claim 7, wherein said substrate is composed of 99.5 percent alumina.

Claim 11

A filter according to claim 8, wherein said substrate and said ground plane is separated by a metal carrier employed to test and adjust said filter prior to providing a final assembly thereof, said testing and adjusting taking place at a point removed from said final assembly.

Claim 12

A filter according to claim 6, wherein said substrate and said ground plane is separated by a metal carrier employed to test and adjust said filter prior to providing a final assembly thereof, said testing and adjusting taking place at a point removed from said final assembly.