A CPW-fed tapered slot antenna with improved time and frequency domain characteristics

In this paper, a miniaturized CPW-fed tapered slot antenna (TSA) with a modified CPW to slot-line transition structure was introduced. An air-bridge and tapered slot edge (TSE) structure was also employed to broaden the transition bandwidth. Through these applied modifications, negative features of the original TSA (limitation of transition) and antipodal Vivaldi antenna (bad cross-polarization) are both removed, while all the positive features remained. Results showed that the proposed structure offered a broad bandwidth of 2.6–20 GHz and also exhibited an appropriate current distribution with high radiation efficiency. The radiation pattern was stable in the working frequency band with good directivity, gain, and low cross-polarization. The proposed antenna structure also presented satisfactory time-domain characteristics. In this study, we confirmed the simulation results through data measurements.

Some further estimates of the prolate spheroidal wave functions and their spectrum

We complete here our recent work on explicit approximations of the Prolate Spheroidal Wave Functions (PSWFs) on the interval [-1,+1] and their associated spectra by pushing forward the methods in view of new results. We give in particular approximations of the ratio between large and small oscillations of PSWFs as well of the transition bandwidth for which the PSWF stops to take its largest values at the boundary of the interval. The aim of this work is two folds. On one hand, we prove a bunch of properties of the PSWFs and on the other hand, we illustrate the theoretical results by some numerical experiments.