Optimized power amplifier

Details Optimized power amplifier Optimized power amplifier

2000-06-15

2001-10-02

Shingleton, Michael B (Department: 2817)

Amplifiers

With plural amplifier channels

Redundant amplifier circuits

C330S302000, C375S238000, C455S126000

Reexamination Certificate

active

06297696

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to power amplifiers which are used in digital wireless telephone applications. Specifically, a power amplifier which has improved reflective power handling capabilities is disclosed.
Portable telephone wireless communication systems employ a battery powered low power radio frequency transmitter circuit coupled to a portable antenna. The usual arrangement includes a telescopic vertical antenna which is fixed to the portable telephone. A problem experienced by the wireless portable telephone is that significant levels of reflected power are experienced due to antenna orientation, and the environment in which the portable telephone is used. The high levels of temporary VSWR seen by the power amplifiers can, besides reducing the effective radiated power, damage the transistors in the final power amplification stages, and, additionally reduce the linearity of the output amplifier. If the reflected power has a constant phase amplitude, due to an unchanging antenna orientation and environment, a matched network could be provided to reduce the reflected power and VSWR. However, the phase and amplitude of the reflected power are constantly changing with the antenna orientation and environment. Accordingly, any attempt to try and match the output amplifier impedance to the antenna impedance must be done dynamically to compensate for the changes in reflected power amplitude and phase.
The present invention has been provided to avoid the consequences of reflected power which continuously changes phase and amplitude.
SUMMARY OF THE INVENTION
A method is disclosed, and a system implementing the method, for reducing reflected power in a radio frequency amplifier. The method and system for implementing the radio frequency amplifier relies upon a balanced amplification of an input signal, wherein the signal to be amplified is split into first and second quadrature related signals. Each of the quadrature related signals are separately amplified in first and second amplifiers, and then recombined in a directional coupler. One of the output ports of the directional coupler is connected to the telephone antenna, while the other port includes a variable load impedance. A sample of the reflected power from the antenna is used to control the variable load impedance so that the port connected to the antenna will be effectively matched to the impedance of the other port, minimizing the amount of reflected power which is transferred by the directional coupler to the connected amplifiers.


REFERENCES:
patent: 3202928 (1965-08-01), Prior
patent: 3643163 (1972-02-01), Bruck
patent: 3842358 (1974-10-01), Frazier
patent: 4070550 (1978-01-01), Miller, Jr. et al.
patent: 4187471 (1980-02-01), Shimoji et al.
patent: 4490684 (1984-12-01), Epsom et al.
patent: 4656434 (1987-04-01), Selin
patent: 4701716 (1987-10-01), Poole
patent: 5101171 (1992-03-01), Redmond
patent: 5381108 (1995-01-01), Whitmarsh et al.
patent: 5420536 (1995-05-01), Faulkner et al.
patent: 5564086 (1996-10-01), Cygan et al.
patent: 5644268 (1997-07-01), Hang
patent: 5732333 (1998-03-01), Cox et al.
patent: 5778308 (1998-07-01), Sroka et al.
patent: 6211734 (2001-04-01), Ahn
patent: 58206212 (1983-01-01), None
patent: 3195205 (1991-03-01), None

Affiliated with

Also associated with

Rating

Optimized power amplifier does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Optimized power amplifier, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optimized power amplifier will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2615947