Integrated microstrip diplexers for radio over fiber

The aim of the paper is to present a new integrated microstrip diplexer applicable in radio over fiber (RoF) links. That integrated microstrip diplexer has a much simpler construction with better characteristics compared to the widely used ones. The attenuation of the diplexer is significantly reduced by integrating the divider with the filters without using isolators between them. Two diplexer samples were designed, constructed and tested. One diplexer is separating (or combining) signals with frequencies of 1,3 GHz and 2,4 GHz. The frequencies of the other diplexer are 2,4 GHz and 2,6 GHz. Due to the integrated construction the size and the attenuation of the diplexers are much smaller compared to the well known, published approaches.