Novel Techniques in Tapered Slot Antenna for Linearity Phase Center and Gain Enhancement

In ultrawideband communications, various parameters are important such as high gain, bandwidth, linear phase center, and endfire pattern. In this letter, endfire tapered slot Vivaldi has been noticed because of its high gain and wide bandwidth, however achieving linear phase center was a big problem. Although the phase of the antenna changes near the aperture area in horn antennas, we have suggested a novel technique using composite aperture structure tomake a linear phase center. Therefore, in our proposed structure, we separated a part of a double exponentially tapered slot antenna from its dielectric with an angle of 8 degrees upwards in the y-axis. In this case, we accomplish increasing the antenna gain and solve the phase center problem. The prototype antenna with added aperture in order to operate in a wide bandwidth shows good performance in 6-18 GHz with VSWR less than 2, and the proposed antenna achieves higher gain, more than 2-4 dBi, in comparison with conventional tapered slot antennas. The antenna is fabricated on Rogers-4003, and experimental results confirm the simulations.