Phase linear class E amplifier for a satellite communication terminal which communicates with a low earth orbiting satellite

• US 5,535,438 A
• Filed: 05/10/1994
• Issued: 07/09/1996
• Est. Priority Date: 05/10/1994
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation Of North America (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Technologies, Inc. (Panasonic Holdings Corporation)
• Inventors: Sevic, John F.
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): Nguyen, Lee
• Application Number:
  US08/240,912
• Time in Patent Office: 791 Days
• Field of Search: 455/110, 455/95, 455/115, 455/116, 455/120, 455/12.1, 375/60, 375/67, 375/297, 330/207 A, 330/251
• US Class Current: 455/110
• CPC Class Codes: H03F 3/2176 Class E amplifiers

Abstract

A low earth orbiting satellite communication terminal includes a data signal generator, a modulator, and a class E switching amplifier. The modulator converts a data signal from the data signal generator into a phase modulated signal which is then amplified by the class E switching amplifier for transmission to a low earth orbiting satellite. In a preferred embodiment, the modulator converts the data signal into a symmetric differential phase shift keyed data signal. The class E switching amplifier amplifies the phase modulated signal at frequencies between about 148 and 150 MHz. The class E switching amplifier includes a switching transistor, an input matching network, a class E load network, and an output matching network. The class E load network is electrically connected to the switching transistor and loads the transistor for phase linear class E operation over a predetermined bandwidth. The class E switching amplifier may include a transistor which is designed to operate at a first predetermined frequency and at a first predetermined voltage, but which is preferably operated below these predetermined levels.

Claims

1. A terminal for communicating with a low earth orbiting satellite comprising:

data signal generation means for generating a data signal for transmission to a low earth orbiting satellite;

modulation means, having an input and an output, said input being electrically connected to said data signal generation means for converting the data signal into a phase modulated data signal;

a class E switching amplifier, having an input and an output, said input of said class E switching amplifier being electrically connected to said output of said modulation means, said class E switching amplifier amplifying the phase modulated data signal into a phase modulated signal at frequencies between 148 and 150 MHz; and

an antenna, electrically connected to said output of said class E switching amplifier, for transmitting the phase modulated signals at frequencies between 148 and 150 MHz to the low earth orbiting satellite.

2. A terminal according to claim 1 wherein said modulation means converts said data signal into a phase shift keyed data signal and wherein said class E switching amplifier is a phase linear class E switching amplifier over a bandwidth between 148 and 150 MHz.

3. A terminal according to claim 2 wherein said modulation means converts said data signal into a symmetric differential phase shift keyed data signal.

4. A terminal according to claim 1 wherein said data signal generation means comprises user input means, responsive to user activation, for accepting input of a user message.

5. A terminal according to claim 1 further comprising a battery power supply, electrically connected to both said data signal generation means and said class E switching amplifier, to thereby produce a portable terminal.

6. A terminal according to claim 1 in combination with a low earth orbiting satellite which receives the phase modulated signals at frequencies between 148 and 150 MHz.

7. A terminal according to claim 1 wherein said class E switching amplifier comprises:

a switching transistor operating at a predetermined switching frequency between 148 and 150 MHz;

DC power supply means for supplying DC power to said switching transistor;

an input matching network, which electrically connects said data signal generation means to said switching transistor;

a class E load network, electrically connected to said switching transistor, which loads said switching transistor for class E operation; and

an output matching network, electrically connected between said class E load network and said antenna.

8. A terminal according to claim 7 wherein said class E load network is a phase linear load matching network which loads said switching transistor for phase linear class E operation over a bandwidth of between 148 to 150 MHz.

9. A class E switching amplifier for amplifying an input signal and driving a load over a predetermined bandwidth, said class E switching amplifier comprising:

a transistor which is designed to operate at a first predetermined frequency which is greater than 800 MHz and at a first predetermined voltage;

power supply means for supplying a second predetermined voltage to said transistor, said second predetermined voltage being less than said first predetermined voltage;

an input matching network, electrically connecting the input signal to said transistor;

a class E load network, electrically connected to said transistor, which loads said transistor for phase linear class E operation at a second predetermined frequency which is between 148 to 150 MHz; and

an output matching network, electrically connected between said class E load network and the load.

10. A class E switching amplifier according to claim 9 wherein said second predetermined frequency is 15% of said first predetermined frequency.

11. A class E switching amplifier according to claim 9 wherein said first predetermined voltage is 12.5 V and wherein said second predetermined voltage is between 4 to 8 V.

12. A class E switching amplifier according to claim 11 wherein said transistor is a cellular transistor designed to operate at first predetermined frequencies between 806 to 960 MHz and wherein said class E load network loads said transistor to operate at second predetermined frequencies of between 148 to 150 MHz.

13. A class E switching amplifier according to claim 9 and further comprising an input signal, electrically connected to said input matching network, said input signal being a phase shift keyed input signal and said class E switching amplifier being a phase linear class E switching amplifier at second predetermined frequencies between 148 to 150 MHz.

14. A class E switching amplifier according to claim 13 wherein said input signal is a symmetric differential phase shift keyed input signal.