Broadband circulator or isolator of the strip line or microstrip type

Claim 2

In a microwave transmission device having ground plane means, planar circuit means adjacent said ground plane means and in parallel relation therewith, said circuit means having a plurality of outwardly narrowing tapering members and a shape such that the impedance thereof is free from abrupt changes, gyromagnetic means disposed over a substantial portion of said tapering members, and magnetic field generating means adjacent said ground plane means for magnetically biasing said gyromagnetic means substantially throughout so that said device operates at nonresonance, whereby the energy in said circuit means travels substantially along the edges thereof, the improvement wherein said ground plane means comprises a layer of conducting material having the portion thereof which overlies said gyromagnetic means formed from a ferromagnetic material, and the remainder formed from a nonmagnetic material, said ferromagnetic portion of said ground plane means being adjacent said magnetic field generating means and situated in the magnetic field generated thereby, whereby the magnetic field applied to said gyromagnetic means is uniform.

Claim 3

A microwave transmission device as recited in claim 1 wherein said gyromagnetic means extends beyond at least the edge of said circuit along which the energy therein flows in a forward direction.

Claim 4

In a microwave transmission device as recited in claim 1 wherein at least one of said tapering members is an input port and at least a second of said tapering members is an output port and wherein said gyromagnetic means overlies the entire surface of said tapering members forming said input and output ports, the improvement wherein said circuit means includes further conductive portions extending from said input and output ports, said further portions having surface areas which are relatively larger than those of said input and output ports and proportioned so that the characteristic impedance thereof is matched to that of the external connections, whereby said circuit means may be more easily connected to the external circuitry.

Claim 5

A microwave transmission device as recited in claim 1 wherein said gyromagnetic means is disposed over substantially all of the tapered portions of the ones of said tapering members which constitute signal input or output ports for said device and the entire edges of said circuit means joining adjacent input and output ports.

Claim 6

A microwave transmission device as recited in claim 1 wherein said ferromagnetic portion is in contact with said gyromagnetic means.

Claim 7

A microwave transmission device as recited in claim 1 wherein said nonmagnetic conducting portion of said ground plane means is formed on the surface adjacent said planar circuit means of a nonmagnetic, nonconducting plate, said ferromagnetic portion being mounted within a recess in said plate.

Claim 8

A microwave transmission device as recited in claim 1 wherein said field generating means is a permanent magnet, said ferromagnetic portion of said ground plane means is highly permeable and is in direct contact with said gyromagnetic means and said magnet, the contacting surfaces of said magnet, said gyromagnetic means, and said ferromagnetic portion being substantially coextensive.

Claim 9

A microwave transmission device as recited in claim 1 wherein said magnetic field generating means is a magnet which is in direct contact with said ferromagnetic portion of said ground plane means along substantially the entire adjacent surface thereof.

Claim 10

A microwave transmission device as recited in claim 8 wherein the adjacent surfaces of said magnet and said ferromagnetic portion are coextensive.

Claim 11

A microwave transmission device as recited in claim 1 wherein said ferromagnetic portion is highly permeable.

Claim 12

A microwave transmission device as recited in claim 10 wherein said ferromagnetic material is formed from cold-rolled steel.

Claim 13

A microwave transmission device as recited in claim 10 wherein said ground plane means comprises an aluminum plate containing said ferromagnetic portion.

Claim 14

A microwave transmission device as recited in claim 10 wherein said ferromagnetic portion is plated with a conducting substantially corrosion resistant material.

Claim 15

A microwave transmission device as recited in claim 11 wherein said ferromagnetic portion is gold plated.

Claim 16

In a microwave transmission device having ground plane means, planar circuit means adjacent said ground plane means and in parallel relation therewith, said circuit means having a plurality of outwardly narrowing tapering members and a shape such that the impedance thereof is free from abrupt changes, gyromagnetic means disposed over a substantial portion of said tapering members, and magnetic field generating means adjacent said ground plane means for magnetically biasing said gyromagnetic means substantially throughout so that said device operates at nonresonance, whereby the energy in said circuit means travels substantially along the edges thereof, the improvement wherein said gyromagnetic means has first and second coplanar portions formed from different materials, said first portion overlying the portion of said circuit means through which the energy in said circuit means normally flows in a forward direction, and said second portion overlying the portion of said circuit containing the reverse flow path for the energy within said circuit means.

Claim 17

In a microwave transmission device having ground plane means, planar circuit means adjacent said ground plane means and in parallel relation therewith, said circuit means having a plurality of outwardly narrowing tapering members and a shape such that the impedance thereof is free from abrupt changes, gyromagnetic means disposed over a substantial portion of said tapering members, and magnetic field generating means adjacent said ground plane means for magnetically biasing said gyromagnetic means substantially throughout so that said device operates at nonresonance, whereby the energy in said circuit means travels substantially along the edges thereof, the improvement wherein said gyromagnetic means has first and second coplanar portions formed from different materials, said first portion overlying the portion of said circuit means through which the energy in said circuit means normally flows in a forward direction, and said second portion overlying the portion of said circuit containing the reverse flow path for the energy within said circuit means.

Claim 18

A microwave transmission device as recited in claim 15 wherein said gyromagnetic means is disposed over substantially all of the tapered portions of the ones of said tapering members which constitute signal input or output ports for said device and the entire edges of said circuit means joining adjacent input and output ports.

Claim 19

A microwave transmission device as recited in claim 15 wherein the said material contained in said first portion of said gyromagnetic means is chosen to have the optimum desired bandwidth, peak power limiting and insertion loss characteristicS in the forward direction of energy flow, and the said material contained in the second portion of said gyromagnetic means is chosen to have the optimum desired isolation characteristic in the reverse direction of energy flow, whereby the peak power handling capabilities of said device are increased while still maintaining a relatively high reverse direction isolation characteristic.

Claim 20

A microwave transmission device as recited in claim 17 wherein one of said tapering members is an input port and a second of said members is an output port; said circuit means having a third member extending outwardly from a portion of said circuit means intermediate said input and output ports, said third member having a length which is long compared to the wave length of the lowest frequency of operation of said device; a layer of lossy material overlying substantially the entire length of said third member in substantially coplanar relationship with and abutting said gyromagnetic means, whereby said layer of lossy material functions as a load for said circuit means; said layer being formed from a material which has a good heat transfer characteristic, and is capable of withstanding the high temperatures occurring during operation of the device; whereby the average power capability of the device is improved.

Claim 21

A microwave transmission device as recited in claim 17 wherein the proportion of said gyromagnetic means constituting said first portion thereof is the minimum proportion which will provide the desired peak power handling capability for the device.

Claim 22

A microwave transmission device as recited in claim 17 wherein said material contained in said first portion of said gyromagnetic material is a material which has been doped to provide a material having a spinwave line width which is greater than that of the material contained in said second portion.

Claim 23

A microwave transmission device as recited in claim 20 wherein the materials contained in said first and second portions of said gyromagnetic means have magnetic saturation value of approximately 1,100 and 1,800 gauss, respectively.

Claim 24

A microwave transmission device as recited in claim 17 wherein said device contains an internal load, said load comprising a lossy material overlying a portion of said circuit means adjacent said second portion of said gyromagnetic means.

Claim 25

A microwave transmission device as recited in claim 22 wherein said lossy material is in contact and substantially coplanar with said second portion of said gyromagnetic means.

Claim 26

In a microwave transmission device having ground plane means, planar circuit means adjacent said ground plane means and in parallel relation therewith, said circuit means having a plurality of outwardly narrowing tapering members and a shape such that the impedance thereof is free from abrupt changes, gyromagnetic means disposed over a substantial portion of said tapering members, and magnetic field generating means adjacent said ground plane means for magnetically biasing said gyromagnetic means substantially throughout so that said device operates at nonresonance, whereby the energy in said circuit means travels substantially along the edges thereof, the improvement wherein one of said tapering members is an input port and a second of said members is an output port; said circuit means having a third member extending outwardly from a portion of said circuit means intermediate said input and output ports, said third member having a length which is at least equal to three wave lengths of the lowest frequency of operation of said device; a layer of lossy material overlying substantially the entire length of said third member in substantially coplanar relationship with and abutting said gyromagnetic means, whereby said layer of lossy material functions as a load for said circuit means; said layer being formed from a material which has a good heat transfer characteristic, and is capable of withstanding the high temperatures occurring during operation of thE device; whereby the average power handling capability of the device is improved.

Claim 27

In a microwave transmission device having ground plane means, planar circuit means adjacent said ground plane means and in parallel relation therewith, said circuit means having a plurality of outwardly narrowing tapering members and a shape such that the impedance thereof is free from abrupt changes, gyromagnetic means disposed over a substantial portion of said tapering members, and magnetic field generating means adjacent said ground plane means for magnetically biasing said gyromagnetic means substantially throughout so that said device operates at nonresonance, whereby the energy in said circuit means travels substantially along the edges thereof, the improvement wherein one of said tapering members is an input port and a second of said members is an output port; said circuit means having a third member extending outwardly from a portion of said circuit means intermediate said input and output ports, said third member having a length which is at least equal to three wave lengths of the lowest frequency of operation of said device; a layer of lossy material overlying substantially the entire length of said third member in substantially coplanar relationship with and abutting said gyromagnetic means, whereby said layer of lossy material functions as a load for said circuit means; said layer being formed from a material which has a good heat transfer characteristic, and is capable of withstanding the high temperatures occurring during operation of thE device; whereby the average power handling capability of the device is improved.

Claim 28

A microwave transmission device as recited in claim 24 wherein said lossy material is silicon carbide.

Claim 29

A microwave transmission device as recited in claim 26 wherein said gyromagnetic means is disposed over substantially all of the tapered portions of the ones of said tapering members which constitute signal input or output ports for said device and the entire edges of said circuit means joining adjacent input and output ports.