Fundamental Limitations of Phased Array Antenna Elements
Abstract
For elements of an infinite planar array, fundamental upper bounds on the impedance matching bandwidth are investigated. Planar arrays in free space, those over a conducting ground plane, and those on a grounded dielectric substrate are considered. For free-space arrays, the bounds are based on the forward scattering sum rule for doubly periodic arrays. For conductor-backed arrays, they are based on the low-frequency expansion of the plane-wave reflection coefficient, following Fano's approach for deriving bandwidth bounds of matching networks, but applied to a scattering configuration. In both cases, the bandwidth upper bounds are expressed in terms of both geometrical (e.g., unit cell dimensions) and electrical (e.g., scan angle, low-frequency polarizabilities) design parameters. Quantitative relations are revealed to find that the bandwidth bounds increase with stronger polarizabilities and smaller cell dimensions. Strong coupling between neighboring elements helps increase the bandwidth via increased polarizability values compared with their isolated counterparts. For conductor-backed arrays, higher-order bandwidth bounds are identified and they include the exact effect of the element design unlike previously known bounds. In addition, the infinite planar array counterparts of the vector effective height and the receiving area of a receiving antenna are found.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 15, 2015
- Accession Number
- AD1020913
Entities
People
- Do-hoon Kwon
Organizations
- University of Massachusetts Amherst