Ultrawideband Superstrate-Enhanced Substrate-Loaded Array With Integrated Feed

A superstrate-enhanced substrate-loaded array (SESLA) with an integrated feed is presented. The design allows for a practical implementation of the SESLA, a concept previously presented by the authors for realizing extremely wideband (> 10:1) low-profile arrays. Specifically, the feed provides unbalanced to balanced transformation allowing the balanced-fed SESLA to be excited with a 50Ω unbalanced line. The resulting array/feed combination is matched across a 13.9:1 bandwidth (infinite array, VSWR ≤ 2.4). When scanned to 45
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in the E-, H-, and D-planes, the unit cell operates across a 13.3:1 bandwidth using a relaxed matching criterion of VSWR ≤ 3. The design is validated through extensive measurement of an 8 × 8 prototype array.