Multiband Antennas Comprising Off-Center-Fed Dipoles for M2M Applications

We have proposed multiband antennas comprising off-center-fed dipoles and trapezoidal elements for small wireless telecommunications modules that actualize Machine-to-Machine applications. Two techniques are employed in the multiband antenna design. The first combines multiple off-center-dipoles to achieve multiband characteristics. The off-center-fed-dipole technique facilitates the adjustment of impedance matching. The second technique employs trapezoidal elements to lower the antenna height and expand the frequency bandwidth by increasing the current pathways. Using these techniques we propose four antennas and one of these achieves operation in multiple bands including the 700 to 900 MHz bands and the 1.7 GHz to 2 GHz bands. The proposed antennas are suitable for M2M applications due to their multiband frequency characteristics and low profiles.