Experimental Study on Isolation Characteristics Between Adjacent Microstrip Lines Employing Periodically Perforated Ground Metal for Application to Highly Integrated GaAs MMICs

Using a periodically perforated ground metal (PPGM) on GaAs monolithic microwave integrated circuit (MMIC), a microstrip line structure with a high isolation characteristic between lines was developed. The high isolation characteristic was originated from a resonance between adjacent microstrip lines employing PPGM. According to experimental results, a much better isolation characteristic was observed from the adjacent microstrip lines employing PPGM compared with conventional microstrip lines, and the frequency range for high isolation was easily controlled by changing the PPGM structure. Above results indicate that microstrip lines employing PPGM are very useful for application to compact signal/bias lines of highly integrated MMIC requiring a high isolation characteristics between lines.