Micro P-coupler
View Patent ↗A coupling loop with each leg connected by two resistors, R 1 and R 2 going to ground on a disk shaped printed circuit board provides a directional coupler with directivity tuned by rotating this disk assembly and coupling controlled by the distance to the main RF transmission line. Once the desired level of directivity is obtained, this board is locked with screws from the top.
1. A microwave coupler assembly, comprising:
a rotatable disk shaped circuit board having first and second major surfaces coated with conductive material, the first and second surfaces respectively having first and second regions of exposed dielectric material without conductive material thereon;
a conductive coupling loop mounted to the first surface of the circuit board in said first region and oriented away from the surface;
first and second resistors connecting the coupling loop to the first conductive surface of the circuit board; and
an RF connector electrically connected to the coupling loop and extending from the second surface of the circuit board in said second region.
2. A microwave coupler assembly as set out in claim 1 , wherein said conductive coupling loop is generally U shaped.
3. A microwave coupler assembly as set out in claim 1 , wherein said circuit board has first and second openings for receiving pins from a test fixture.
4. A microwave coupler assembly as set out in claim 2 , wherein said first and second resistors are electrically connected to opposite ends of said U shaped conductive coupling loop and to said conductive first surface of said circuit board.
5. A combined microwave test fixture and directional coupler assembly, comprising:
a directional coupler assembly comprising a coupler fixture housing having an input port, a through port, a coupled port, and a decoupled port, an adjustable coupler structure mounted in a bore of the coupled port of the housing, the coupler structure comprising a conductive rotatable disk shaped circuit board, a conductive coupling loop mounted to the circuit board at a dielectric portion thereof and oriented into the bore of the housing, first and second resistors electrically connecting the coupling loop to the circuit board, a RF connector electrically connected to the coupling loop and also extending from the opposite side of the circuit board from the coupling loop, and a test fixture mating connector on the circuit board; and
a test fixture assembly comprising a directivity adjustment connector adapted to mate with the test fixture mating connector on the circuit board and an RF connector adapted to mate with the RF connector on the circuit board;
wherein the disk is adjustable by turning the test fixture to rotate the disk shaped circuit board and change the direction of the loop in the housing and alter the directivity of the coupling of said coupled port.
6. A microwave test fixture and directional coupler assembly as set out in claim 5 , wherein said test fixture mating connector comprises first and second holes in the circuit board and wherein said directivity adjustment connector of said test fixture comprises matching mating pins.
7. A microwave test fixture and directional coupler assembly as set out in claim 5 , wherein said test fixture assembly comprises a housing having first and second screws and threaded holes in the housing and an inner opening receiving the RF connector and, wherein the RF connector is locked in place in the housing by engaging it by the set screws.
8. A microwave test fixture and directional coupler assembly as set out in claim 5 , wherein the coupler fixture housing includes an inner cavity, wherein a through coupler is configured within the cavity between the input and coupled ports.
9. A microwave test fixture and directional coupler assembly as set out in claim 5 , wherein the coupled port is measurable at different loop orientations from the RF connector of the test fixture assembly.
10. A microwave test fixture and directional coupler assembly as set out in claim 5 , further comprising a second coupler structure configured in a second bore in said coupler fixture housing.
11. A method of adjusting a microwave directional coupler assembly, comprising:
inserting a coupler assembly comprising a disk shaped circuit board, a conductive loop and RF connector in a bore in a coupler housing;
rotating the disk shaped circuit board using a separate test fixture adapted to mate with the disk shaped circuit board;
measuring RF power using a connector configured in the test fixture;
locking the disk shaped circuit board in place using set screws engaging the top edge of the circuit board and holes in the housing; and
removing the test fixture.