DESIGN OF SUB-MILLIMETER DIPLEXER USING MICROSTRIP LINES

Abstract

As we know that, instrumentation in millimetre and sub-millimetre astrophysics requires high value of spectral resolution. This problem can be overcome by means of multi-frequency detector array. In this project, sub-millimetre diplexer is designed using microstrip lines since microstrip lines can be printed directly onto a circuit board and have low cost and are easily fabricated. A diplexer, is an essential component in multi-service and multi-band communication systems, is a three terminal device that separates the input signals to two output ports. Diplexing is used to prevent inter modulation and keep reflected power (VSWR) to a minimum for each input transmitter and frequency. While diplexers can combine a relatively wide bandwidth, the major limitation comes with the antenna itself, which must be sufficiently wideband to accept all of the signals being passed through it, and transfer them to the air efficiently. We designed a sub-millimetre diplexer using microstrip lines which operates at frequency 150 GHz & 220 GHz. With the help of S parameters, we can see that theour diplexer gives good transmission at 150 GHz and 220 GHz, and also it provides good attenuation at non-required frequencies.