Compact all-metallic cavity-cascaded antenna

A compact all-metallic cavity-cascaded antenna is presented. A twoendshorted metallic plate is shorted and divided averagely by five identical shorting walls alternatively, forming five alternatively cascaded open cavities. By selecting proper width of the metallic plate and length of the shorting walls, all the five open cavities operate in the TM_1n0 (n = 0.5) mode, generating five fringing fields with the same phase. Thus, effective radiation is achieved. The proposed antenna is operated in the 5-order mode, e.g. five standing waves are distributed along the proposed antenna. It only occupies a volume of 0.43λ₀ × 2.83λ₀ (λ₀ is the wavelength of the centre frequency). Moreover, the proposed antenna is fabricated by all metal, resulting in low cost, light weight, wide bandwidth, high gain and high efficiency. A prototype that can provide an overlapped impedance bandwidth and 3 dB gain bandwidth of 7.72% from 8.10 to 8.75 GHz and a peak gain of 13.37 dBi at 8.5 GHz is built and measured.