Semiconductor switches and switching circuits for microwave

Abstract

The purpose of the present invention is to provide a small-sized switch attaining high isolation of not less than 80 dB, maintaining low insertion loss also in high frequencies not less than 60 GHz. A semiconductor switch according to the present invention utilizes FETs a gate electrode, a source electrode, and a drain electrode of each of which are formed on a semiconductor. The source electrode and the drain electrode are connected with the earth as well as are disposed in parallel to each other, and the gate electrode is formed between the source electrode and the drain electrode, and both the ends of the gate electrode are connected to the first input-output terminal 1 and the second input-output terminal.

What is claimed is:  
     
         1 . A semiconductor switch comprising: 
 a first electrode, a second electrode, and a third electrode formed on a semiconductor substrate;    said first electrode and said second electrode connected with the earth and are disposed in parallel to each other,    said third electrode formed between said source first and said second electrode;    a first terminal coupled to one end of said third electrode; and    a second terminal coupled to the other end of said third electrode.    
     
     
         2 . The switch is claimed in  claim 1 , wherein said first electrode is a drain electrode of a transistor, said second electrode is a source electrode of said transistor, said third electrode is a gate electrode of said transistor.  
     
     
         3 . The switch is claimed in  claim 1 , wherein said first electrode is a first cathode electrode of a diode, said second electrode is a second cathode electrode of said diode, said third electrode is an anode electrode of said diode.  
     
     
         4 . The switch is claimed in  claim 1 , wherein said first electrode is a first anode electrode of a diode, said second electrode is a second anode electrode of said diode, said third electrode is a cathode electrode of said diode.  
     
     
         5 . A switching circuit comprising: 
 a coplanar transmission line having a signal line, conductors arranged such that said signal line is sandwitched between the conductors, said conductors applied to ground potential;    an element having a first electrode coupled to said coplanar transmission line, a second electrode, a third electrode, said second and third electrodes applied to ground potential; and    a signal terminal coupled to said coplanar transmission line.    
     
     
         6 . The switching circuit is claimed in  claim 5 , wherein said first electrode is a drain electrode of a transistor, said second electrode is a source electrode of said transistor, said third electrode is a gate electrode of said transistor.  
     
     
         7 . The switching circuit is claimed in  claim 5 , wherein said first electrode is a first cathode electrode of a diode, said second electrode is a second cathode electrode of said diode, said third electrode is an anode electrode of said diode.  
     
     
         8 . The switching circuit is claimed in  claim 5 , wherein said first electrode is a first anode electrode of a diode, said second electrode is a second anode electrode of said diode, said third electrode is a cathode electrode of said diode.  
     
     
         9 . The switching circuit as claimed in  claim 5 , wherein said first, second, and third electrode are formed on a substrate including an AlGaAs layer and an InGaAs layer.