Coupled oscillator arrays are being examined as a means of beam steering for antenna arrays. A progressive linear phase shift can be established across a linear coupled oscillator array. The phase difference between array elements can be changed, which results in beam steering. It is hoped that this new method can replace currently used control circuitry for antenna arrays at millimeter wavelengths. The complex circuitry used for beam steering today requires a large number of phase shifters, and becomes cumbersome for arrays at very short wavelengths. One problem with coupled oscillator arrays is the presence of phase noise. A proposed solution to this is to inject the input signal at multiple points within the array. The phase of the injected signal at each point would differ, conforming to the ideal phase progression expected from the array.
A linear nine-element coupled oscillator array is being built at Clemson University this summer to test this solution. The signal from each oscillator will be sent to an antenna. The first objective will be to adjust the free running frequencies of the voltage controlled oscillators so that they mutually lock at the same frequency. Then the oscillator array will be injection locked at one, three, and five different points. The change in phase noise for each scenario will be observed by measuring the radiation pattern transmitted by the antenna array. The tradeoff between decreased phase noise and increased use of phase shifters for signal injection will then be examined.
For a description of work done over the summer to investigate this, read the written report (Microsoft Word document, 926KB).
View the slides used in the final oral presentation (Microsoft PowerPoint Presentation, 633KB).
Look at the layout for the poster used in the poster session (Microsoft PowerPoint Presentation, 3.15MB).
[Home]