Abstract A bandwidth reconfigurable monopole antenna with disc-shaped is presented in this article. This integrated a and cascaded bandpass structure, four different states can be adjusted by the structure. By switching diode’s on-off state switch quickly among whose fractional range from 16% to 55% centered at around 1.8 GHz. The experiment also shows good stable electromagnetic properties of ...

In this paper, we present an analytical model to analysis the kirk effect onstatic and dynamic responses of quantum well heterojunction bipolar transistor lasers(HBTLs). Our analysis is based on solving the kirk current equation, continuityequation and rate equations of HBTL. We compare the performance (current gain,output photon number and small signal modulation bandwi...

Broadcasting offers a bandwidth-efficient way of delivering popular content in media-on-demand (MoD) systems. Harmonic windows scheduling (HWS) is a mathematical framework that is relevant to bandwidth minimization in MoD broadcasting. Given c channels, the optimal HWS problem tries to schedule as many pages of a video as possible in the c channels. Let κ be the largest integer n satisfying Hn ...

This paper reports on assessment of an e-readiness model for low bandwidth environment. The main focus of the model is on technological (bandwidth) related critical factors that are barrier to the adoption of technology mediated learning in developing countries, among others. The study used three survey questionnaires; Institutional Survey Questionnaire, Lecturers Perception Questionnaire, and ...

the modulation response, relative intensity noise and frequency noise characteristics of qd lasers are investigated theoretically, in presence of an additional optical pumping. it is revealed that the modulation response of qd laser enhances under additional optical beam. by small signal analysis of the carriers' and photons' rates, it is proposed that by injecting excess carriers to ...

A new design of coplanar waveguide (CPW)-fed antenna with circular polarization (CP) and excellent impedance matching is presented. In this design a pair of circular-shaped slits is applied to opposite corners of the slot for enhancing the impedance matching and realizes bandwidth of 134.43% across 2.98-15.20 GHz for VSWR≤2. Furthermore this structure exhibits axial ration bandwidth (ARBW) of 3...

The limited audio bandwidth of narrowband telephone speech degrades the speech quality. This paper proposes a method that extends the bandwidth of telephone speech to the frequency range 0–300 Hz. The lowest harmonics of voiced speech are generated using sinusoidal synthesis. The energy in the extension band is estimated from spectral features using a Gaussian mixture model. The amplitudes and ...

In this paper we merge recent developments on exact algorithms for finding an ordering of vertices of a given graph that minimizes bandwidth (the BANDWIDTH problem) and for finding an embedding of a given graph into a line that minimizes distortion (the DISTORTION problem). For both problems we develop algorithms that work in O(9.363) time and polynomial space. For BANDWIDTH, this improves O(10...

The graph bandwidth problem is a well-known NP-complete problem. The relation between size of a graph and bandwidth is very interesting. The minimum size required in G with bandwidth B is denoted as m(n, B) while the graph G of order n and bandwidth B with size m(n, B) is called an extremal graph. This paper provides the minimum size for a graph of odd order n, n ≥ 9, and bandwidth (n + 1)/2, a...