In this paper a compact one unit cell mu negative (MNG) zeroth-order resonator (ZOR) antenna is designed and analyzed. A ZOR antenna based on the MNG transmission line (TL) has been previously introduced. The feeding structure of the previously presented MNG antenna is a microstrip line in parallel with the antenna. This feeding mechanism enlarges the overall size of the antenna and also increases the cross polarization level of the radiated fields. In this paper we propose a MNG TL based ZOR antenna with a coaxial feed and with a specific matching mechanism which results in compactness of the antenna and reducing its cross polarization level. An approximate design method for the proposed antenna is presented using its equivalent circuit and according to its operation mechanism. A prototype antenna has been fabricated and tested. The measured return loss and radiation patterns are given and the overall performance of the antenna is compared with some of the previously reported compact metamaterial antennas.

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