A high-efficiency reconfigurable element for dynamic metasurface antennas (DMA), consisting of a complimentary electric-LC (CELC) resonator fed through the cavity from a waveguide slot, is proposed in this paper, with positive-intrinsic-negative (PIN) diodes loaded to realize the coding performance. To begin with, the low efficiency problem of a traditional CELC element is demonstrated before the introduction of the proposed element. Subsequently, an equivalent circuit is illustrated to analyse

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... the resonant performance, with extensive parametric study for verification. The proposed element has a low ohmic loss when the diode is switched on, 25 times less than the traditional element. Furthermore, the radiation efficiency of a DMA with 10 proposed elements is compared with a traditional design, showing a significant efficiency improvement from 25% to 75% when half diodes are switched on. Finally, measurements are conducted to verify the feasibility of the dynamic element to achieve radiation ON and OFF states, showing a 12 dB radiation gain difference between two states. INDEX TERMS Dynamic metasurface antenna, high efficiency, metasurface, PIN diode, reconfigurable.