Characteristics of Planar Monopole Antenna on High Impedance Electromagnetic Surface

This paper presents for the first time measured characteristics of a planar monopole antenna placed directly on a high impedance electromagnetic surface or artificial magnetic conductor (AMC). The return loss and radiation patterns are compared between the antenna in free space, and when placed directly on a perfect electrical conductor (PEC), and on the AMC. The antenna measured in free space has a wide pass band from 3 to 10 GHz. The return loss for the antenna on the PEC is nearly all reflected back and the return loss for the antenna on the AMC has a 10 dB bandwidth from 7.5 to 9.5 GHz. The gain of the antenna in free space, on PEC and on AMC is 1, -12 and 10 dBi, respectively. This indicates that the AMC is working properly, sending all the radiation outward with little loss

Tunable Reduced Size Planar Folded Slot Antenna Utilizing Varactor Diodes

A tunable folded slot antenna that utilizes varactor diodes is presented. The antenna is fabricated on Rogers 6006 Duriod with a dielectric constant and thickness of 6.15 and 635 m, respectively. A copper cladding layer of 17 m defines the antenna on the top side (no ground on backside). The antenna is fed with a CPW 50 (Omega) feed line, has a center frequency of 3 GHz, and incorporates Micrometrics microwave hyper-abrupt 500MHV varactors to tune the resonant frequency. The varactors have a capacitance range of 2.52 pF at 0 V to 0.4 pF at 20 V; they are placed across the radiating slot of the antenna. The tunable 10 dB bandwidth of the 3 GHz antenna is 150 MHz. The varactors also reduce the size of the antenna by 30% by capacitively loading the resonating slot line. At the center frequency, 3 GHz, the antenna has a measured return loss of 44 dB and a gain of 1.6 dBi. Full-wave electromagnetic simulations using HFSS are presented that validate the measured data. Index Terms capacitive loading, Duriod, folded slot antenna, varactor

Assignments for a project oriented digital design laboratory course

A project oriented laboratory manual is presented as a complement to the theoretical part of a digital design course. The manual is organized into assignments that are to be completed by the student independently, without the benefit of a teaching assistant. The first group of assignments concentrates on digital design background material. With a solid base the student can proceed to more involved assignments. Furthermore, the assignments following the background material explore concepts indispensable in the formation of competitive design engineers. A summary of the implications of this type of laboratory assignments is presented in the conclusions

A Study of Metadata Element Co-Occurrence

Purpose – This paper aims to investigate the internet web page metadata usage behavior in terms of their metadata element co-occurrences. Metadata are designed to facilitate both web publishers/authors to organize their web pages and search engines to index the web pages accurately

Pedagogy for Librarians

Most librarians are required to take classes on reference, collection development, and information organization in library school; courses on pedagogy, on the other hand, are usually optional, if they’re offered at all. This leads most librarians who end up with instruction duties to learn on the job. Activities and assessments can be learned on the fly fairly easily, but these often have little to no bearing on how much students actually absorb and recall weeks later because alone, they are usually insufficient to ensure deep learning. This chapter seeks to add the basics of pedagogy, a subject comprehensively covered in K-12 teacher preparation programs, to the librarian’s instructional repertoire