Distributed constant circuit with active element

Details Distributed constant circuit with active element Distributed constant circuit with active element

2000-05-26

2001-12-11

Smith, Matthew (Department: 2825)

Semiconductor device manufacturing: process

Making field effect device having pair of active regions...

Having schottky gate

C438S172000, C257S194000

Reexamination Certificate

active

06329231

ABSTRACT:

This application is based on Japanese Patent Application HEI 11-151174, filed on May 31, 1999, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
a) Field of the Invention
The present invention relates to a negative resistance line using an active element having at least three terminals.
b) Description of the Related Art
Ultra high speed pulse transmission techniques in the order of 100 G bits/sec are being developed in the age of high capacity and high speed communications. In order to transmit a pulse at such high speed, an ultra broadband amplifier is required which has a gain-bandwidth product in the order of tera Hz and is terminated at 50&OHgr; without power reflection. In order to meet such requirements, a distributed progressive wave amplifier using high performance high electron mobility transistors (HEMT) are being developed. A gain-bandwidth product of 150 GHz can be realized by a distributed progressive wave amplifier using HEMTs.
Although the gain-bandwidth product of 150 GHz can be obtained by a distributed progressive amplifier using HEMTs, its power gain is smaller than a performance expected from a cutoff frequency f
t
of HEMT and distributed constant effects. The reasons of the lower performance than expected may be no incorporation of distributed constants into each HEMT, a limit of the number of cascade connections, a limit of fine segmentation of a line length, a mutual conductance G
m
lowered by a phase matching gate stub line, and the like.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a distributed constant line applicable to an ultra broadband amplifier.
According to one aspect of the present invention, there is provided a distributed constant line comprising: an active element including first and second regions and a control electrode, carriers moving between the first and second regions in a first direction and a motion of carriers being controlled by an electric signal applied to the control electrode, the first and second regions and the control electrode extending in a second direction crossing the first direction from an input terminal to an output terminal; a conductive region electrically connected to the first region from the input terminal to the output terminal; a trigger line extending in the second direction for propagating an electric signal from the input terminal to the output terminal in the second direction, the electric signal propagating the trigger line being applied to the control electrode at a corresponding position in the second direction; and an output line extending in the second direction for propagating an electric signal from the input terminal to the output terminal in the second direction, the electric signal propagating on the output line in the second direction being excited by carriers moving through the active element in the first direction.
The electric signal propagating along the trigger line in the second direction controls a motion of carriers of the active element at each position in the second direction. An amplified electric signal therefore appears on the output line and propagates along the output line in the second direction. By properly setting the performance of the active element and the wavelength constant of each line, a negative resistance line can be obtained.


REFERENCES:
patent: 5805023 (1998-09-01), Fukuden
patent: 6075414 (2000-06-01), Nagaoka et al.
patent: 63-216380-a (1988-09-01), None
patent: 2000-340788-A (1999-05-01), None
Yang et al. “A compact and wideband GaAs-hemt distributed amplifier IC based on a Micro-machined CPW” IEEE MTT-S digest 0-7803-5687-x/00 pp. 213-216. No date.

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