Cavity-backed slot antenna for thin wireless portable devices

A conventional cavity-backed slot antenna (CBSA), excited by a probe, requires a large space due to the size of the resonant cavity especially at lower frequencies. An alternative CBSA antenna can be designed by using a compact non-resonant cavity where the slots are excited. This paper presents such a CBSA for dual-band (2.4 GHz and 5 GHz) Wi-Fi applications for an ultra-thin portable wireless device (like tablet or laptop) with the thickness in the range of 4 mm to 5 mm. The presented antenna is L-shaped and can be placed at the corner of the device. The antenna meets the efficiency requirement that is greater than -7 dB in the 2.4 GHz band and greater than -6 dB in the 5 GHz band. Hence, the presented antenna is a suitable candidate of Bluetooth/Wi-Fi antenna for slim laptops or tablets.