A system includes a cap having an opening, and a septum configured to engage with the cap. One radiation detector includes a semiconductor substrate, at least one cathode on a surface of the semiconductor substrate, and a plurality of anodes on a surface of the semiconductor substrate opposite the at least one cathode, wherein the plurality of anodes have gaps therebetween. Methods of making the same are also provided. In accordance with the configuration of the matching circuit, it is possible to achieve a reduction in insertion loss, an improvement in the reflection characteristics of an associated antenna, and, thus, an improvement in bandpass characteristics.