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US 5,256,996 AGranted
Integrated coplanar strip nonlinear transmission line
AssigneeThe Board of Trustees of the Leland Stanford Junior University
InventorsRobert A. Marsland, Mark J. W. Rodwell, David M. Bloom
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Abstract
An integrated coplanar strip nonlinear transmission line comprising a substrate of gallium arsenide upon which a heavily doped buried layer and a lightly doped surface layer of epitaxially grown gallium arsenide are grown. Two parallel conductors are integ This work was funded by the United States Government's Office of Naval Research under contract No. N99914-85-K-0381. The United States Government has a paid up license in this technology.
Claims35
A nonlinear transmission line comprising:
- a substrate of semiconductor material;
- first and second parallel conductors formed on a surface of said substrate so as to form an integrated coplanar strip transmission line;
- a plurality of semiconductor junctions electrically isolated from each other and distributed along said integrated coplanar strip transmission line and formed in said substrate, each said junction having one side coupled to said first conductor and having the other side coupled to said second conductor and each said junction having a junction capacitance which varies with the voltage existing between said first and second conductors at any particular time at the location of said junction.
An integrated coplanar strip nonlinear transmission line comprising:
- a substrate of semiconductor;
- a buried layer of doped epitaxially grown semiconductor formed on one surface of said substrate and doped to an impurity concentration high enough to substantially reduce the resistivity of said buried layer;
- a surface layer of lightly doped epitaxially grown semiconductor formed on a surface of said buried layer;
- first and second conductors integrated on said surface layer so as to form a coplanar strip transmission line having a predetermined characteristic impedance;
- wherein at least said buried layer and said layer of lightly doped epitaxially grown semiconductor have formed therein electrically isolated islands surrounded by areas of semiconductor which is substantially nonconductive, said islands being spaced along said substrate between said parallel first and second conductors;
- junction means integrated in said isolated islands and electrically coupled to said first and second conductors for loading said transmission line with capacitive inductance with a value at each island which varies with the voltage difference across the line at any particular time at the corresponding island and for causing the overall characteristic impedance of said transmission line including the impedance of said junction means to be a predetermined value.
3 more elements
An integrated nonlinear transmission line, comprising:
- a semiconductor substrate having a heavily doped buried layer and a lightly doped surface layer and having spaced apart electrically isolated islands surrounded by areas of semiconductor which are substantially nonconductive, each electrically isolated island including within its perimeter portions of conductive semiconductor in said surface and buried layers;
- two parallel conductors integrated on said surface so as to be parallel and spaced far enough apart to yield a transmission line having a characteristic impedance which is substantially higher than the desired overall characteristic impedance for said nonlinear transmission line;
- means integrated in said isolated islands and electrically coupled to said two parallel conductors for causing the group velocity for propagation of signals down said transmission line to be voltage dependent at each point along said transmission line.
An apparatus comprising:
- transmission line means formed on a semiconductor substrate having an input terminal and an output terminal for receiving an input signal and guiding said input signal to said output terminal;
- and
- voltage dependent capacitance means coupled to said transmission line for causing the group velocity for propagation of said input signal to said output signal to be voltage dependent at each point along said transmission line so as to render said transmission line nonlinear and cause compression of the transition time of an input step transition propagating along said transmission line, and further comprising means for reducing high frequency losses so as to not stop said compression process, and further comprising means for reducing dispersion effects on said input signal so as to not stop said compression.
An apparatus comprising:
- a semiconductor substrate having a heavily doped buried layer of semiconductor material formed thereon and a more lightly doped top layer of semiconductor material formed on top of said buried layer, said buried layer and said top layer being rendered nonconductive in selected regions so as to form a plurality of spaced apart electrically isolated islands of semiconductor material from said buried layer and said top layer, said top layer having electrical conductors forming a transmission line on the surface thereof;
- at least one junction between materials having different fermi levels formed in each said island, each said junction having a junction area and each having a transition capacitance at the junction area which is voltage dependent, each said junction being coupled to the electrical conductors of said transmission line such that said transition capacitance is subjected to the voltage difference of any input signal propagating down said line such that the transition capacitance is varied by said voltage difference thereby making the transmission line nonlinear such that the group velocity of signals propagating down said nonlinear transmission line is voltage dependent.
Dependencies are inferred from the claim text.