Low-loss infrared filter for microwave measurement which integrates a distributed bragg reflector into a microwave transmission line

1. A method of configuring a microwave apparatus, the method comprising:

providing a microwave system configured to output a microwave readout signal, the microwave system having an input and an output;

connecting an output microwave transmission line to the output of the microwave system; and

configuring a distributed Bragg reflector, integrated into a transmission line geometry, as a low-loss infrared filter that blocks infrared radiation while allowing transmission of the microwave readout signal, the low-loss infrared filter being connected to the output microwave transmission line.

2. The method of claim 1 , wherein the distributed Bragg reflector comprises a unit cell of at least two different dielectric layers.

3. The method of claim 2 , wherein the unit cell repeats to have a total of N dielectric layers.

4. The method of claim 1 , wherein the distributed Bragg reflector comprises a first dielectric layer and a second dielectric layer adjacent to the first dielectric layer.

5. The method of claim 4 , wherein the first dielectric layer has a first dielectric constant; and

wherein the second dielectric layer has a second dielectric constant different from the first dielectric constant.

6. The method of claim 4 , wherein the first dielectric layer has a first thickness; and

wherein the second dielectric layer has a second thickness.

7. The method of claim 6 , wherein the first thickness is different from the second thickness.

8. The method of claim 4 , wherein the low-loss infrared filter has a center conductor stripline formed through the first dielectric layer and the second dielectric layer.

9. The method of claim 8 , wherein the center conductor stripline is a conductive metal;

wherein the low-loss infrared filter has an outer conductor encompassing the first dielectric layer and the second dielectric layer, the center conductor stripline extending through the outer conductor in a lengthwise direction;

wherein the low-loss infrared filter comprises a first connector and a second connector, both connected to opposite ends of the center conductor stripline in the lengthwise direction; and

wherein an outer conductor of the first and second connectors connects to the outer conductor of the low-loss infrared filter.