Low cost microstrip filters and mixers at 43 GHz

This paper has shown a technique for fabricating mm-wave filters and mixers on a low cost PTFE substrate. These designs can be implemented without the use of via holes or restrictive etching dimensions and tolerances, whilst achieving good performance. The coupled line filter offers good rejection performance over wide frequency ranges, whereas the LAST type filter offers rejection at particular frequencies whilst achieving a lower insertion loss in the passband. The mixer is a balanced passive design offering a conversion loss of 11.5 dB and an input referred TOI of +7.6 dBm for an LO power of +10 dBm. A combination of the filter and mixer designs can be utilised to provide a simple up or down-convertor with good attenuation of unwanted products such as the image frequency