ULTRA-WIDEBAND PLANAR ANTENNA ARRAYS BASED ON RECURSIVE-PERTURBATION DESIGN TECHNIQUES
Open Access
- Author:
- Spence, Thomas George
- Graduate Program:
- Electrical Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- October 06, 2008
- Committee Members:
- Douglas Henry Werner, Dissertation Advisor/Co-Advisor
Douglas Henry Werner, Committee Chair/Co-Chair
Kultegin Aydin, Committee Member
Victor P Pasko, Committee Member
Brian Lewis Weiner, Committee Member - Keywords:
- broadband arrays
aperiodic arrays
wideband arrays
antenna arrays - Abstract:
- This dissertation addresses the need for robust methodologies that are capable of designing ultra-wideband antenna arrays. In order to achieve this level of performance it is necessary to look toward non-periodic, or aperiodic, element distributions. Unlike the widely studied and rather straightforward design of periodic arrays, the design of aperiodic arrays typically involves complex and often non-intuitive element distributions. Adjusting, or perturbing, element locations based on a periodic lattice is one of the traditional approaches but it lacks the ability appreciably extend the bandwidth of an array. Moreover, it has only been shown to be well suited for linear arrays with a relatively small number of elements, not medium to large-N arrays which would require the adjustment of many element locations. This dissertation introduces a design methodology that looks toward iteratively constructed geometries to mitigate these limitations. Rather than adjusting every element location in an array, it is based on adjusting a small number of elements and then exploiting the recursive properties of these geometries to generate large array distributions. A key aspect of this approach is that it reduces the representation of arbitrarily large-N planar arrays to a very small set of parameters. This is significant because it provides for a tractable design problem. Additionally, with a small set of parameters, these methodologies are easily combined with a global optimizer for a robust optimization procedure. The efficacy of the concept of recursive-perturbation will be demonstrated through the introduction of two design techniques. One of these techniques is based on exploiting space-filling curves to generate highly modular, ultra-wideband planar arrays. This approach is explored through several examples, including a 962-element array that maintains a sidelobe level below –10 dB over more than a 10:1 bandwidth. The other technique is based on a perturbation scheme that is incorporated into the basic aperiodic tiling generation process. A variety of examples will be investigated to demonstrate its versatility, including a design that maintains a sidelobe level below –11 dB over more than a 22:1 bandwidth. In addition to ultra-wide bandwidths, there are a number of other desirable properties associated with the arrays of these design techniques, including highly sparse apertures and modular architectures.