A wideband periodic leaky-wave antenna (LWA) is proposed in this paper. By using lossy dielectric material inside the wedge-like guide as medium for wave propagation, a leaky mode excited and results widening bandwidth. For certain tangential losses, achieves 20.34% 3-dB gain bandwidth with maximum of 19.7 dBi. The experiences low side lobe level (SLL) general cross-polarization over operating ...

This paper describes a beam scanning antenna loading a movable dielectric plate on a microstrip comb-line antenna. This antenna uses the mechanical system that has the characteristic of an easy structure as well as low costs. The comb, a radiation element, is connected to a microstrip line. The beam direction of the proposed antenna changes according to phase shifts of the microstrip line movin...

We have designed, fabricated, and experimentally characterized a lens for the THz regime based on artificial dielectrics. These are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. For example, the well-known dielectric property, the refractive index, which usually has a value greater than unity, can...

Material properties in radio frequency and microwave regimes are limited due to the lack of molecular resonances at these frequencies. Metamaterials are an attractive means to realize a prescribed permittivity or permeability function, but these are often prohibitively lossy due to the use of inefficient metallic resonators. All-dielectric metamaterials offer excellent potential to overcome the...

Traveling Wave Tubes (TWTs) consist of different elements. The most important element of TWT is the RF circuit. RF circuits in helix TWTs need a dielectric support to hold the helix; this support also has an effect in electromagnetic properties of RF circuits. A novel dielectric support is proposed to reduce the second harmonic of helix TWTs. The dielectric support in this structure consists of...

This paper presents a new model to calculate the characteristic impedance and wave propagation constant of a microstrip line made of a superconducting material. Modelling provides the only tool for designing superconducting microstrip based circuits because no direct measurements of such a line can be made at millimetre and sub-millimetre waves and at cryogenic temperature of 4 K with required ...

In this study, we investigate the transparency of an overdense inhomogeneous plasma slab. This anomalous transmission is achieved when the conditions provided for the incident electromagnetic wave to excite coupled surface waves on the both sides of the slab. These conditions require that the homogeneous overdense plasma, or the metallic film, is placed between two dielectric layers. Here, the ...

This paper presents the design of a small planar antenna with triangular patch for WiMax application. A conventional ground plane has been modified to reduce the size and increasing the bandwidth as well as to cover the WiMax band. The triangular‐shaped patch is placed on top of the substrate and parasitic patch is placed at other side. By inserting a triangular patch in the coplanar ground pla...

We present mm-wave transmission as a complementary technique to characterize the properties of superconducting thin lms, obtaining information on both the real and imaginary part of the dielectric function. Examples are given to illustrate the strength of the technique to measure the response of dielectric materials and strati ed systems. We demonstrate the BCS-behavior of a conventional superc...