Wave transmission lines and networks – Coupling networks – With impedance matching
Reexamination Certificate
2002-06-18
2004-03-30
Tokar, Michael (Department: 2819)
Wave transmission lines and networks
Coupling networks
With impedance matching
C333S034000, C333S246000, C333S238000
Reexamination Certificate
active
06714095
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to constant “R” networks and, more particularly to a tapered constant “R” network for use in high power, high frequency distributed amplifiers.
BACKGROUND OF THE INVENTION
High powered, high frequency distributed amplifiers are well known in the art, having been around since the 1940's. Distributed or traveling wave techniques have been used to design distributed amplifiers comprising microwave GaAs FETs that operate from 2.0 to 20 GHZ. A discussion of distributed amplifier design is taught in the book entitled “Microwave Circuit Design Using Linear and Non-Linear Techniques” published by John Wiley & Sons in 1990, pages 350-369.
The aforementioned prior art reference teaches the use of both constant K and constant R networks comprising series inductances and shunt capacitances, the latter of which is generally provided by the parasitic drain-to-source capacitance of a FET that is coupled between the series inductances of the network. Multiple sections of these networks are generally cascaded together and, by adjusting the individual phase shift therethrough, the respective gains of each FET stage will add along the associated transmission lines, as is well understood.
Prior art constant “R” distributed amplifiers as aforementioned have generally been fabricated on GaAs substrates. Because the GaAs substrate is formed of a single layer, the efficiency and bandwidth of these amplifiers has been limited. One reason for this is that mutual conductance coupling factor of the series inductances is limited since the series inductance is formed, for an example, by using interwoven spiral transmission lines formed on the surface of the single layer substrate.
Hence, a need exists for an improved, high efficiency, broadband power amplifier.
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patent: 5436601 (1995-07-01), Mandai et al.
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patent: 5977850 (1999-11-01), Chaturvedi
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patent: 2001036372 (2001-02-01), None
“GaAs MESFET distributed baseband amplifier IC with allpass filter network,” S. Kimura et al., Electronics Letters, Oct. 29, 1998, vol. 34, No. 22, pp. 2124-2126.
“Reduction of the chip area of MMIC distributed amplifiers,” A. Boifot et al., European Transactions on Telecommunications and Related Technologies, (1990) May/Jun., No. 3, pp. 277-281.
Pavio Anthony M.
Zhao Lei
Koch William E.
Mai Lam
Tokar Michael
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