Title :
A new concept to cancel insertion phase variation in MMIC amplitude controller
Author :
Roques, D. ; Cazaux, J. ; Pouysegur, M.
Author_Institution :
Alcatel Espace, Toulouse, France
Abstract :
A concept which keeps a very low insertion phase variation in an analog monolithic microwave IC (MMIC) amplitude controller is presented. This new approach, applicable to dual-gate FET (DGFET) variable-gain amplifiers, is to connect an active variable load to the second gate of the DGFET. This load makes use of a cold FET (with Vds=0 V) whose impedance varies depending on the amplitude command of the circuit. Then, the cold FET compensates the insertion phase change introduced by the DGFET attenuation control over a wide dynamic range. Based on this principle, a C-band GaAs MMIC attenuator for active antenna application has been designed. The phase variation versus gain is always lower than +or-2 degrees over a 20-dB gain/attenuation range.<>
Keywords :
MMIC; attenuators; field effect integrated circuits; linear integrated circuits; microwave amplifiers; C-band; GaAs; MMIC; active antenna application; active variable load; amplitude controller; analog monolithic microwave IC; attenuator; dual-gate FET; insertion phase variation cancellation; variable-gain amplifiers; Analog integrated circuits; Attenuation; Dynamic range; Gallium arsenide; Impedance; MMICs; Microwave FET integrated circuits; Microwave FETs; Microwave integrated circuits; Monolithic integrated circuits;
Conference_Titel :
Microwave and Millimeter-Wave Monolithic Circuits Symposium, 1990. Digest of Papers., IEEE 1990
Conference_Location :
Dallas, TX, USA
DOI :
10.1109/MCS.1990.110939
