Shielded enclosure for testing wireless communication devices

• US 6,657,214 B1
• Filed: 06/16/2000
• Issued: 12/02/2003
• Est. Priority Date: 06/16/2000
• Status: Expired due to Term

• Current Assignee: ETS-Lindgren LP (ESCO Technologies, Inc.)
• Original Assignee: EMC Test Systems LP (ESCO Technologies, Inc.)
• Inventors: Chen, Zhong, Foegelle, Michael D., Liu, Kefeng, Sayler, Bryan H.
• Primary Examiner(s): Lee, John R.
• Assistant Examiner(s): Vanore, David A.
• Application Number:
  US09/595,732
• Time in Patent Office: 1,264 Days
• Field of Search: 250/496.1, 250/497.1, 250/498.1, 250/503.1, 250/505.1, 250/506.1, 250/515.1, 333/212, 333/227, 333/228, 333/229, 333/230, 333/231, 333/232
• US Class Current: 250/506.1
• CPC Class Codes: G01R 29/0821 rooms and test sites therefor, e.g. anechoic chambers, open field sites or TEM cells for testing antennas G01R29/105
• CPC Class Codes: H01Q 17/00 Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems
• CPC Class Codes: H04B 17/16 Test equipment located at the transmitter
• CPC Class Codes: H04B 17/29 Performance testing

Abstract

A test system having a shielded enclosure and common air interface for testing the transmit and receive functionality of wireless communication devices such as mobile phones. A test system according to the present invention provides improved fault coverage by permitting robust testing of the entire signal path of a wireless device, including the antenna structure. In one embodiment of the invention, an RF-shielded enclosure having a test chamber is provided. The structure of the shielded enclosure blocks ambient RF energy from entering the test chamber and interfering with testing operations. The shielded enclosure may be lined with an RF absorbing material to improve test repeatability. A novel test antenna structure is disposed in the test chamber for wirelessly communicating test signals to a device under test. The test antenna is designed to maximize coupling with the antenna(s) of one or more types of wireless devices, while also minimizing variations in test measurements that might result from the particularized location of batteries or processing circuitry within such devices. The test antenna is coupled to an RF connector that provides a connection point for an external test set functioning as a base-station simulator for use in testing all or a subset of the features of the device under test. The test antenna may be formed on a printed circuit board. In one such embodiment, the elements of the test antenna are formed on a printed circuit board, with the element nearest the antenna of the device under test formed on the side of the circuit board nearest the device under test. The remainder of the test antenna is formed on the opposite side of the printed circuit board.

Claims

1. A test system for testing wireless and other devices, comprising:

a shielded enclosure forming a test chamber for receiving a device under test;

an antenna having one or more elements disposed in the test chamber for wirelessly communicating test signals to and/or from a device under test; and

a printed circuit board, at least one element of the antenna formed on the printed circuit board.

2. The test system of claim 1, the antenna comprising at least a first antenna element and a second antenna element, both the first and second antenna elements formed on the printed circuit board.

3. The test system of claim 2, wherein the first element and second element are asymmetric.

4. The test system of claim 2, the first and second antenna elements formed on opposite sides of the printed circuit board.

5. The test system of claim 4, the first antenna element having a greater surface area than the second antenna element, the second antenna element disposed on the side of the printed circuit board furthest away from the area of the test chamber used to receive a device under test.

6. The test system of claim 2, the antenna having an RF feedline, the first and second antenna elements having a parabolic shaped portion nearest the RF feedline, the first and second antenna elements having generally rectangular shaped distal ends.

7. The test system of claim 2, the first and second antenna elements formed in a bow-tie arrangement.

8. The test system of claim 1 wherein the antenna comprises a dipole antenna.

9. The test system of claim 1 wherein the antenna comprises a bi-conical dipole antenna.

10. The test system of claim 1, the antenna having a coupling coefficient providing a relatively flat response over a frequency range of approximately 700 megahertz to 2 gigahertz.

11. A test system for testing wireless and other devices, comprising:

a shielded enclosure forming a test chamber for receiving a device under test;

an antenna having one or more elements disposed in the test chamber for wirelessly communicating test signals to and/or from a device under test; and

a clamp assembly, disposed in the test chamber, for maintaining a device under test in a communicative relationship with the antenna.

12. The test system of claim 11, further comprising:

an RF cable connection disposed on the periphery of the shielded enclosure for coupling the antenna to an external signal analyzer/generator,

a printed circuit board, at least one element of the antenna formed on the printed circuit board.

13. The test system of claim 11, further comprising:

a cable connection for providing a direct cable connection to a device under test.

14. The test system of claim 11, further comprising:

an RF-absorbent material lining a substantial portion of the test chamber.

15. The test system of claim 11, wherein the shielded enclosure substantially isolates the test chamber from external RF energy.

16. The test system of claim 11, wherein the shielded enclosure is generally rectangular in shape, and comprises a top portion movable between a sealed position and an open position.

17. The test system of claim 11, wherein the shielded enclosure comprises at least one sealable opening for use in an automated test environment, wherein a device under test is mechanically positioned in the shielded enclosure via the sealable opening.

18. A test environment for testing wireless and other devices, comprising:

a shielded enclosure forming a test chamber;

an antenna disposed in the test chamber for wirelessly communicating test signals to and/or from a device under test;

a cable communicatively coupled to the antenna; and

a printed circuit board, at least one element of the antenna formed on the printed circuit board.

19. The test environment of claim 18, further comprising:

a test set communicatively coupled to the antenna via the cable, the test set analyzing and/or generating signals communicated between the antenna and a device under test.

20. The test environment of claim 19, further comprising:

a computer coupled to the test set, the computer configurable to perform analytical operations on data generated by the test set.

21. The test environment of claim 19, the antenna comprising at least a first antenna element and a second antenna element, the first and second antenna elements formed on opposite sides of the printed circuit board.

22. A method for testing wireless and other devices, comprising:

providing a test system, the test system comprising a shielded enclosure forming a test chamber, the test system further comprising a test antenna disposed in the test chamber;

coupling a test set to the test system such that the test set is able to receive signals from and provide signals to the test antenna;

positioning a wireless device in the test chamber such that the wireless device is communicatively coupled to the test antenna;

communicating test signals between the test set and the wireless device via the test antenna; and

wherein the test antenna comprises at least a first antenna element and a second antenna element, the first and second antenna elements formed on opposite sides of a printed circuit board.