Sliding phase shifters for use in phased array antennas are disclosed. According to one aspect, a sliding phase shifter includes a fixed dielectric having first striplines to couple power into the sliding phase shifter. The sliding phase shifter also includes a sliding dielectric having second striplines electrically slidingly coupled to the first striplines. An amount of phase shift is determined by an amount of overlap of the first striplines and the second striplines, a width of the second striplines being at least partially tapered along a portion of the second striplines to improve performance.