ISM band to U-NII band frequency transverter and method of frequency transversion

• US 20050255821A1
• Filed: 04/21/2005
• Published: 11/17/2005
• Est. Priority Date: 06/14/2001
• Status: Active Grant

• Current Assignee: Dale Hensley, Jeffrey David Stepp
• Original Assignee: Dale Hensley, Jeffrey David Stepp
• Inventors: Stepp, Jeffrey David, Hensley, Dale
• Granted Patent: US 7,107,015 B2
• Time in Patent Office: Days
• US Class Current: 455/323
• CPC Class Codes: H04B 1/00 Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
• CPC Class Codes: H04B 1/005 adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
• CPC Class Codes: H04B 1/0096 where a full band is frequency converted into another full band
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes

Abstract

A frequency transverter (10) and method for enabling bi-frequency dual-directional transfer of digitally encoded data on an RF carrier by translating between a crowded or otherwise undesirable first frequency band, such as the 2.4 GHz ISM band, and a less-crowded or otherwise desirable second frequency band, such as the 5.0 GHz-6.0 GHz U-NII band. In a preferred embodiment, the transverter (10) connects between an existing data radio (11) and its existing antenna (30), and comprises a bandswitch (12); an input RF isolating device (14); a transmuter (16); a converter (18); a dual output local oscillator (20); an output RF isolating device (22); and an antenna (24) tuned to the second frequency band. The bandswitch (12) allows for bypassing the transverter (10), thereby facilitating its use with legacy systems. The transmuter (14) and converter (16) are adapted to convert to and from, respectively, the second frequency band.

Claims

1. A transverter operable to translate a transmit signal and a receive signal between a first frequency band and a second frequency band, wherein the transverter is connected between a data radio and an existing antenna tuned to the first frequency band, the transverter comprising:

a bandswitch interposed between the data radio and the existing antenna and adapted to allow for selectively directing the transmit signal from the data radio to the existing antenna, thereby substantially bypassing the transverter;

a transmuter connected to the input isolating device and adapted to translate the transmit signal from the first frequency band to the second frequency band;

a converter connected to the input isolating device and adapted to translate the receive signal from the second frequency band to the first frequency band, wherein a noise figure characteristic of the converter is matched to a path loss difference between the first frequency band and the second frequency band; and

an antenna connected to the output isolating device and tuned to the second frequency band and adapted to transmit the transmit signal and to receive the receive signal.

2. The transverter as set forth in claim 1, wherein the first frequency band is approximately 2.4 GHz, and the second frequency band is approximately between 5.0 GHz and 6.0 GHz.

3. The transverter as set forth in claim 1, wherein both the transmit signal and the receive signal include digitally encoded data modulated onto an RF carrier.

4. The transverter as set forth in claim 1, wherein both the transmit signal and the receive signal have time division duplex characteristics.

5. The transverter as set forth in claim 1, wherein the bandswitch is a single-pull double-throw absorptive switch adapted to provide low insertion loss, high linearity, and high isolation between the first frequency band and the second frequency band.

6. The transverter as set forth in claim 1, wherein the bandswitch includes a one-bit control line adapted for controlling the directing of the transmit signal from the data radio to the existing antenna.

7. The transverter as set forth in claim 1, wherein the transmuter includes a first input terminal and a second input terminal, and further includes—

an attenuator adapted to receive the transmit signal from the input isolating device and to attenuate the transmit signal and to allow for adjusting throughput gain between the first input terminal and the second input terminal, and further adapted to provide a broadband match for both the input isolating device and the data radio;

a frequency conversion device following the attenuator and adapted to translate the attenuated transmit signal from the first frequency band to the second frequency band;

a bandpass filter following the frequency conversion device and adapted to filter the transmit signal to substantially remove an undesirable signal element;

an amplifier stage following the bandpass filter and adapted to amplify the transmit signal; and

a low-pass filter following the amplifier stage and adapted to filter the transmit signal to reduce a spurious element above the second frequency band.

8. The transverter as set forth in claim 7, wherein the attenuator of the transmuter has an attenuation value of at least 10 dB.

9. The transverter as set forth in claim 7, wherein the frequency conversion device of the transverter includes a double-balanced mixer having sufficient drive power to minimize a conversion loss to less than 10 dB.

10. The transverter as set forth in claim 7, wherein the amplifier stage of the transmuter is a GaAs device operable to provide approximately 1 Watt of output power.

11. The transverter as set forth in claim 1, wherein the converter includes—

a bandpass filter adapted to filter the receive signal to substantially remove an undesirable signal element;

a low noise amplifier stage following the bandpass filter and adapted to amplify the receive signal, and further adapted to provide a low noise figure and an additional gain at the second frequency band;

a frequency conversion stage following the low noise amplifier stage and adapted to translate the receive signal from the second frequency band to the first frequency band;

a low-pass filter stage following the frequency conversion stage and adapted to filter the amplified receive signal to reduce a spurious element outside the second frequency band;

an amplifier stage following the low-pass filter stage and adapted to amplify the translated receive signal; and

an attenuator following the amplifier stage and adapted to reduce a total gain through the converter.

12. The transverter as set forth in claim 11, wherein the low noise amplifier stage of the converter includes a pHEMT device with excellent low-noise characteristics at microwave frequencies.

13. The transverter as set forth in claim 1, wherein the antenna has a standard helix design wherein wire is wound in a λ

circumference with a ¼

λ

pitch over a λ

diameter ground plane to provide a bandwidth covering substantially the entire second frequency band, and further providing approximately between 6 dB and 20 dB of gain.

14. The transverter as set forth in claim 1, wherein the transverter is provided as a 5 inch diameter by 1 inch high package using a double-stacked material with an internal aluminum ground plane.

15. The transverter as set forth in claim 1, wherein at least a portion of the transverter is constructed using a ceramic PTFE substrate.

16. The transverter as set forth in claim 1, further comprising an input isolating device connected to the bandswitch and adapted to electrically isolate one or more components of the transverter from the data radio.

17. The transverter as set forth in claim 16, wherein the input isolating device provides electrical isolation of approximately between 15 dB and 20 dB.

18. The transverter as set forth in claim 16, wherein the input isolating device is a Y-junction ferrite device configured as a three-port circulator device adapted to provide a non-reciprocal effect, and wherein the input isolating device exhibits a third order symmetry behavior.

19. The transverter as set forth in claim 16, wherein the input isolating device has a narrowband design operable to reduce a lower frequency spurious element from the transmit signal.

20. The transverter as set forth in claim 16, wherein the input isolating device has a drop-in microstrip design operable to facilitate placement directly on a substrate material.

21. The transverter as set forth in claim 1, further comprising a dual output local oscillator connected to both the transmuter and the converter and adapted to provide a drive level thereto.

22. The transverter as set forth in claim 21, wherein the dual output local oscillator is adapted to generate an LO signal, the dual output local oscillator including—

a phase-locked-loop adapted to set a fundamental frequency of the LO signal, wherein the fundamental frequency determines how translation occurs between the first frequency band and the second frequency band;

a fundamental frequency amplifier adapted to amplify the LO signal;

a frequency multiplier adapted to reduce the fundamental frequency of the LO signal by one-half; and

first and second narrow-band harmonic frequency amplifiers adapted to provide the LO signal to both the transmuter and the converter while increasing electrical isolation between the transverter and the converter.

23. The transverter as set forth in claim 22, wherein the first and second narrow-band harmonic frequency amplifiers each include a high pass filter followed by an RF amplifier followed by a low-pass filter.

24. The transverter as set forth in claim 1, further comprising an output isolating device connected to both the transmuter and the converter and adapted to electrically isolate the transverter.

25. The transverter as set forth in claim 24, wherein the output isolating device provides electrical isolation of approximately between 15 dB and 20 dB.

26. The transverter as set forth in claim 24, wherein the output isolating device is a Y-junction ferrite device configured as a three-port circulator device adapted to provide a non-reciprocal effect, and wherein the output isolating device exhibits a third order symmetry behavior.

27. A transverter operable to translate a transmit signal and a receive signal between a first frequency band and a second frequency band, wherein the transverter is connected between a data radio and an existing antenna tuned to the first frequency band, the transverter comprising:

a bandswitch connected directly to an antenna output of the data radio and to the existing antenna and adapted to allow for selectively directing the transmit signal from the data radio to the existing antenna, thereby substantially bypassing the transverter;

an input isolating device connected to the bandswitch and adapted to electrically isolate one or more components of the transverter from the data radio;

a transmuter connected to the input isolating device and adapted to translate the transmit signal from the first frequency band to the second frequency band;

a converter connected to the input isolating device and adapted to translate the receive signal from the second frequency band to the first frequency band, wherein a noise figure characteristic of the converter is matched to a path loss difference between the first frequency band and the second frequency band;

a dual output local oscillator connected to both the transmuter and the converter and adapted to provide a drive level thereto;

an output isolating device connected to both the transmuter and the converter and adapted to electrically isolate the transverter; and

an antenna connected to the output isolating device and tuned to the second frequency band and adapted to transmit the transmit signal and to receive the receive signal.