Multiband Open-Ended Resonant Antenna Based on One ECRLH Unit Cell Structure

In this letter, a microstrip-fed open-ended resonant antenna (RA) based on an extended composite right/left-handed (ECRLH) unit cell structure is presented for multiband operations. This antenna includes an asymmetric ECRLH unit cell as the main resonator and a short microstrip line as the feeding line. This designed RA, of overall size of 56 × 64 × 1.575 mm $^3$ , generates ten operating resonances covering several commercial frequency bands over 0.5–6 GHz. Measured and simulated results have close agreement. Furthermore, the equivalent circuit model of the proposed RA is developed. For each operating resonance, the major control parts in this antenna structure and the primary radiation sources for each operating resonance are analyzed and summarized.