Multiband film antenna comprising offset fed dipole elements using inkjet printer for M2M applications

We propose a multi-band film antenna comprising offset fed dipole elements using an inkjet printer for machine-to-machine (M2M) applications. The proposed antenna is based on a folded offset-fed dipole antenna structure and is constructed from a Polyethylene terephthalate sheet. The point of the proposed approach is to employ a tapered element in order to broaden the bandwidth in a high band including W-CDMA (Bands I, II, IV, and V) and LTE (Band 1). The proposed antenna achieves operation in multiple frequencies in a low band including LTE (Band 28), GSM 900 (E-GSM 900), and W-CDMA (Band VI), and in the high band. We achieve a compact antenna with the Voltage Standing Wave Ratio (VSWR) (≤2) bandwidth of 31.2% in the low band, and a VSWR bandwidth (≤2) of 14.5% in the high band. The proposed antenna has omni-directional patterns in all operating bands. In addition, we utilize an inkjet printing fabricating process using a home-use inkjet printer with a conductive ink cartridge. Frequency characteristics are analyzed using a simulator based on the method of moments, and the validity of the numerical results is shown based on measured VSWR characteristics of the prototype antenna. The proposed antenna can be affixed onto a variety of equipment and is low cost. Therefore, the proposed antenna is well suited to M2M applications.