Microwave doherty amplifier
US5420541A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 4, 1993 |
| Grant date | May 30, 1995 |
| Priority date | — |
| Expiry date | Jun 4, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F1/0288
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An improved Doherty amplifier for operation at microwave frequencies using microstrip circuit technology and gallium arsenide devices to achieve greater efficiency and linearity. The circuit divides the input power equally between a carrier amplifier and peak amplifier with a quarter-wave delay at the input to the peak amplifier insuring that the output power of the two amplifiers will be in phase at the load. A three-port network combines the phase-delayed carrier amplifier output with the output of the peak amplifier. The outputs of the two amplifiers are connected together by a quarter wave transmission line of impedance R. A load of one-half the optimum load (R/2) is attached to the output of the peak amplifier. A quarter-wave line section provides the transition from R/2 to the desired impedance, R. When the peak amplifier is off, its output impedance is infinite and the output power of the carrier amplifier is delivered entirely to the load. As the peak amplifier becomes more active, it delivers more of its output power to the load while its output current gradually reduces the effective load impedance seen by the carrier amplifier thus allowing it to deliver more power. In t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.