A Low-profile and Longilineal Dual-Band Antenna

This letter presents a low-profile, longilineal dual-band shorted patch antenna designed for applications in narrow and elongated spaces. By etching a vertical slot, four resonant modes of the shorted patch are tuned to achieve dual-band operation. The bandwidth of each band is extended to 200 MHz by incorporating the parasitic modes of parasitic patches on either side into each band separately. The proposed antenna features a low profile of $0.011 \lambda_{L}$ and a longilineal shape of $0.711 \lambda_{\mathrm{L}} \times 0.113 \lambda_{\mathrm{L}}$ ($\lambda_{\mathrm{L}}$ refers to the vacuum wavelength at the lowest frequency of the operation band). Simulations indicate that the impedance bandwidths of -6 dB are $3.4-3.6 \mathrm{GHz}$ and $4.8- 5.0$ GHz, respectively, with average total efficiencies of -3.02 dB and -3.00 dB, respectively.