CPW-fed Slotted Monopole antenna for WLAN applications

Since the FCC has announced to allow the unlicensed use of the industrial, scientific, and medical (ISM) frequency band by any potential users, wireless communications community has provided enormous opportunities for driving many wireless systems that can be communicated over short distances. For example, some practical applications are operated at the internationally available unlicensed ISM band of 2.4 GHz such as the Bluetooth or wireless local-area network (WLAN) systems and of 5.2 and 5.8 GHz like the WLAN systems [1]. IEEE 802.11 b/g is allocated at the band of 2.4-2.484 GHz, while IEEE 802.11a is at the band of 5.15-5.35 GHz and 5.725-5.825 GHz. To meet these standards, it is proposed to design a single antenna that can cover all these bands [2]. In particular, a great interest in coplanar waveguide (CPW)-fed antennas has been suggested because of their many attractive features such as wide bandwidth, good impedance matching, simple structure of a single metallic layer, no soldering point, and easy integration with active devices or monolithic microwave integrated circuits [3]. The antennas with cross-slot, H-shaped narrow slot, circular slot [4]-[6] with narrow bandwidth at 2.4 GHz WLAN band have been reported. And CPW-fed slotted antenna with two separate and symmetrical ground planes is proposed [7]. In [8] the CPW antenna with asymmetrical ground planes is investigated with narrow bandwidth at the operating band. In this paper, a novel dual-band patch antenna consisting of a slotted monopole and a CPW feeding structure with asymmetrically surrounded ground planes with slots is proposed. By properly optimizing the shapes of the embedded slots on the rectangular patch, dual-band operation and good radiation performance, suitable for wireless communication such as the 2.4/5 GHz WLAN systems, has been achieved. Details of the antenna design and experimental results are presented and discussed.