High electron mobility transistor

Abstract

A novel radiofrequency signal processing system such as an LMDS transceiver is disclosed. The radiofrequency signal processing system includes a receive switch with an input terminal connected to receive an incoming radiofrequency signal. A first signal reception processing block with an input terminal connected to a first output terminal of the receive switch processes the incoming radiofrequency signal within a first frequency band. A second signal reception processing block with an input terminal connected to the second output terminal of the receive switch processes the incoming radiofrequency signal within a second frequency band. A transmit switch has an output terminal connected to transmit an outgoing radiofrequency signal. A first signal transmission processing block with an output terminal connected to the first input terminal of the transmit switch processes the outgoing radiofrequency signal within a third frequency band. A second signal transmission processing block with an output terminal connected to the second input terminal of the transmit switch processes the outgoing radiofrequency signal within a fourth frequency band. A controller coupled to the transmit and receive switches causes the receive switch to transmit the incoming radiofrequency signal to a selected one of the first and second signal reception processing blocks, and causes the transmit switch to receive the outgoing radiofrequency signal from a selected one of the first and second signal transmission processing blocks. Multiple frequency ranges may therefore be handled by a single LMDS transceiver, enabling low-cost mass production of the transceiver.

I claim:  
     
         1 . A radiofrequency signal processing system comprising: 
 a radiofrequency signal processing device having an input terminal and an output terminal;    a DC blocking system having a quad arrangement of capacitive elements, the DC blocking system being coupled between a radiofrequency input signal source and the input terminal of the radiofrequency signal processing device;    an RF filter system having a quad arrangement of capacitive elements, the RF filter system being coupled between the DC blocking system and a ground node; and    a diode system having a quad arrangement of diode elements, the diode system being coupled in series with the DC blocking system between the radiofrequency input signal source and the input terminal of the radiofrequency signal processing device.    
     
     
         2 . The radiofrequency signal processing system of  claim 1 , wherein each capacitive element comprises a capacitor.  
     
     
         3 . The radiofrequency signal processing system of  claim 1 , wherein each capacitive element of the DC blocking system comprises a quad arrangement of capacitors.  
     
     
         4 . The radiofrequency signal processing system of  claim 1 , wherein each diode element comprises a diode.  
     
     
         5 . The radiofrequency signal processing system of  claim 1 , wherein each diode element comprises a quad arrangement of diodes.  
     
     
         6 . The radiofrequency signal processing system of  claim 1 , further comprising a second diode system having a quad arrangement of diode elements, the second diode system having an input terminal connected to a first side of the quad arrangement of diode elements and an output terminal connected to a second side of the quad arrangement of diode elements, the input terminal of the second diode system being coupled to the output terminal of the radiofrequency signal processing device.  
     
     
         7 . A radiofrequency signal processing system comprising: 
 a receive switch having an input terminal connected to receive an incoming radiofrequency signal, the receive switch having first and second output terminals;    a first signal reception processing block operable to process the incoming radiofrequency signal within a first frequency band, the first signal reception processing block having an input terminal connected to the first output terminal of the receive switch;    a second signal reception processing block operable to process the incoming radiofrequency signal within a second frequency band, the second signal reception processing block having an input terminal connected to the second output terminal of the receive switch;    a transmit switch having an output terminal connected to transmit an outgoing radiofrequency signal, the transmit switch having first and second input terminals;    a first signal transmission processing block operable to process the outgoing radiofrequency signal within a third frequency band, the first signal transmission processing block having an output terminal connected to the first input terminal of the transmit switch;    a second signal transmission processing block operable to process the outgoing radiofrequency signal within a fourth frequency band, the second signal transmission processing block having an output terminal connected to the second input terminal of the transmit switch; and    a controller coupled to the transmit and receive switches, the controller being operable to cause the receive switch to transmit the incoming radiofrequency signal to a selected one of the first and second signal reception processing blocks, the controller being operable to cause the transmit switch to receive the outgoing radiofrequency signal from a selected one of the first and second signal transmission processing blocks.    
     
     
         8 . The radiofrequency signal processing system of  claim 7 , wherein the first and third frequency bands are identical, and wherein the second and fourth frequency bands are identical.  
     
     
         9 . A high electron mobility transistor, comprising: 
 a III-V compound semiconductor substrate    a channel layer of In X Ga l−X As formed over the semiconductor substrate, wherein X is in the range of 0.15 to 0.30 inclusive, the channel layer having a thickness in the range of 100 to 200 angstroms inclusive;    a barrier layer formed over the channel layer;    a gate contact formed over the barrier layer; and    source and drain regions formed over the substrate.    
     
     
         10 . The high electron mobility transistor  claim 9 , wherein the transistor a part of an amplifier.