SYSTEMS AND METHODS FOR SIMULATING A MULTIPATH RADIO FREQUENCY ENVIRONMENT

• US 20100285753A1
• Filed: 05/04/2010
• Published: 11/11/2010
• Est. Priority Date: 05/06/2009
• Status: Active Grant

• Current Assignee: ETS-Lindgren LP (ESCO Technologies, Inc.)
• Original Assignee: ETS-Lindgren LP (ESCO Technologies, Inc.)
• Inventors: Foegelle, Michael
• Granted Patent: US 8,412,112 B2
• Time in Patent Office: Days
• US Class Current: 455/67.12
• 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: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04B 17/29 Performance testing
• CPC Class Codes: H04B 17/3911 Fading models or fading generators

Abstract

Embodiments include systems and methods for simulating a multipath environment for testing a device. In one embodiment, a plurality of antennas are placed around a device under test in an anechoic chamber. Each of a plurality of the antennas is connected to a path of a variable path simulator capable of generating multiple paths between the antennas and external wireless communication test equipment. The variable path simulator introduces a delay spread into each path. In this way, a multipath environment is simulated with signals appearing to arrive from different angles and different distances. Each of a plurality of antennas may be adapted to produce substantially plane waves at the device under test.

Claims

1. A method of simulating a multipath environment, the method comprising:

placing a plurality of antennas at various angles around a device under test within an anechoic chamber, each of the plurality of antennas adapted to produce substantially plane waves at the device under test;

connecting the plurality of the antennas to a variable path simulator having multiple separate paths to introduce user-defined delay spreads into each path connected to an antenna, wherein each path of the variable path simulator is coupled to a different one of the plurality of antennas; and

receiving or transmitting by the plurality of antennas, a plurality of signals, each signal associated with a different one of the plurality of antennas, and wherein each signal propagates through a separate one of the multiple separate paths of the variable path simulator to enable simulation of reflections and interference sources at different angles and distances.

2. The method of claim 1, wherein at least one of the plurality of antennas is formed from an array of antenna elements.

3. The method of claim 2, wherein excitation of the antenna elements is phased to form a phased array.

4. The method of claim 3, wherein the phased array is excited to produce a main beam at an acute angle with respect to a face of the array.

5. The method of claim 2, wherein the array of antenna elements is encompassed by absorbing material.

6. The method of claim 1, wherein the plurality of antennas do not lie in a common plane.

7. The method of claim 1, wherein each of the plurality of antennas is adapted to produce substantially plane waves at the device under test by placing a dielectric lens in a path of a main beam of the antenna.

8. The method of claim 1, wherein each of the plurality of antennas is adapted to produce substantially plane waves at the device under test by placing a reflector in a path of a main beam of the antenna.

9. The method of claim 8, wherein each antenna is placed behind absorbing material and a parabolic reflector redirects the main beam of the antenna past the absorbing material.

10. A test system for testing a device in a multipath environment, the test system comprising:

a plurality of antennas disposed at various positions around the device under test within an anechoic chamber, each of the plurality of antennas adapted to produce substantially plane waves at the device under test; and

a variable path simulator with different paths connected to different ones of the plurality of antennas to introduce a different delay spread into each path connected to an antenna;

wherein the positions of the antennas and the delays introduced by the variable path simulator enable simulation of electromagnetic fields from reflections and interference sources at different angles and distances.

11. The test system of claim 10, wherein one or more of the antennas is an array of flared-notch antenna elements encircled by absorbing material.

13. The test system of claim 10, wherein each of the plurality of antennas is a horn antenna adapted to produce substantially plane waves by placing a dielectric lens in a path of a main beam of the horn antenna.

14. The test system of claim 10, wherein each of the plurality of antennas is a horn antenna adapted to produce substantially plane waves by placing a parabolic reflector in a path of a main beam of the horn antenna.

15. The test system of claim 14, further comprising absorbing material positioned between a horn antenna and the device under test.

12. The test system of 11, wherein the flared-notch antenna elements are arranged to provide dual polarization.

16. A system for simulating a multi-path environment, the system comprising:

a plurality of antennas, each antenna adapted to produce substantially plane waves at a device under test;

a simulator to simulate a plurality of spatial paths, each spatial path coupled to a different one of the plurality of antennas,

a Multiple Input Multiple Output (MIMO) tester to measure a signal in each of M emulated channels coupled to N spatial paths of the simulator, where M and N are integers.

17. The system of claim 16, wherein the plain-wave-producing antennas are configured to produce a non-plane wave at the device under test.

18. The system of claim 16, wherein each of the plurality of antennas is a phased array of antenna elements.

19. The system of claim 16, wherein each antenna includes a dielectric lens in a path of a main beam of the antenna.

20. The system of claim 16, wherein each antenna includes a reflector in a path of a main beam of the antenna.