In the comparison in Table III, the antenna proposed in this study uses three switches to achieve 2³ states, which is the maximum number of reconfigurable states. Compared with previous FRAs, this antenna has a smaller size and achieves more states using fewer switches.

In far-field situation, the proposed antenna aims to maintain bidirectional radiation characteristics in the E-plane (yz-plane) and nearly omnidirectional pattern in the H-plane (xz-plane) for all the eight states, which is in accordance with the far-field patterns of typical printed MMA. This work is tested in an anechoic chamber. Fig. 6 shows the simulated and measured far-field results at state 111, where radiation patterns are most possibly changed because of the dc supplies for the three switches. The simulated far-field results still agree well with the measured output. The simulated gain for all states varies from 1.11 dBi to 1.59 dBi, where the peak gain is obtained at state 000 because all switches are turned off, and the radiation efficiency is larger than 84%. However, the measured peak gain is 0.5 dBi because the p-i-n diodes and many lumped elements introduce some losses.

Conclusion: A 3-bit frequency reconfigurable meander-line MMA is proposed. The antenna has 2³ = 8 independent narrow band states. The number of states is optimally large in terms of the number of switches used because of the antenna’s binary reconfigurability. The measured results agree well with the simulated ones, and good impedance matching characteristics and acceptable bandwidth are achieved on each state, covering a considerable frequency range from 1.01 GHz to 1.54 GHz. This antenna has similar far-field radiation characteristics as the traditional MMA and features in immensely miniaturized size.