Dispersion Reduction in a Coaxial Transmission Line Bend by a Layered Approximation of a Graded Dielectric Lens

Abstract

In an electrically large square coaxial transmission line, we demonstrated preservation of a narrow impulse during propagation through a relatively tight 90° bend compensated by a layered approximation of a CID lens. By use of a non-linear global optimization algorithm, we established that the layered dielectric design was essentially optimal. In terms of the observed, raw impulse response, the compensated bend increased the pulse width by only 15 ps, to 70 ps, from the 55 ps observed for an equivalent length of straight transmission line. In contrast, without compensation, the transmission line bend distorted the impulse into a bipolar signal spread over a 500 ps time interval.