We present a quantization procedure for the electromagnetic field in a circular cylindrical cavity with perfectly conducting walls, which is based on the decomposition of the field. A new decomposition procedure is proposed; all vector mode functions satisfying the boundary conditions are obtained with the help of this decomposition. After expanding the quantized field in terms of the vector mo...

Abstract—A novel circularly polarized cavity-backed antenna (CBA) excited by crossed bowtie dipoles is presented in this paper. It is fed by a transition from a microstrip line to doubleslot lines. The crossed dipoles consist of a top-loaded triangular and a filleted rhombic to achieve the required input impedance relations for circularly polarized radiation. After optimization, a simulated 3-d...

We study symmetries in multi-transverse-mode near-fields of circular vertical cavity surface emitting lasers (VCSELs). The 0◦ polarized component of the near-field always has circular or high-order rotational symmetry, indicating that all significant optical properties of the laser are isotropic for light of that polarization. In contrast, the simultaneously present 90◦ polarized part of the sa...

This chapter discusses an ab-initio frequency-domain model of circular microresonators, built on the physical notions that commonly enter the description of the resonator functioning in terms of interaction between fields in the circular cavity with the modes supported by the straight bus waveguides. Quantitative evaluation of this abstract model requires propagation constants associated with t...

In this paper we consider the design of a four-cavity microwave circuit for a high-gain K-band gyroklystron. The goal is to use this device to test a high gradient linear accelerator structure. The frequency doubling circular gyroklystron uses a beam voltage of 500 kV, beam current of 200 A in the circular TE011 mode and provides an output in the TE021 mode. We study the behavior of the four-ca...

The formulation of the wall admittance of a circular microstrip antenna by the spectral domain method is presented. The circular microstrip antenna is calculated using the cavity model. The electromagnetic fields within the antenna cavity are determined from the impedance boundary condition at the side aperture. The contribution from the region outside the antenna is taken into account by the w...

A novel transition structure based on Substrate Integrated Circular Cavity (SICC) is proposed in this paper. The design approach of the transition structure can also be used in other operating frequency. Good performance of flexibility and S-parameters were observed for the new transition structure. Different design tools were used to validate the design method.

Objective. The purpose of this study was to investigate safety and feasibility of some surgical approaches to the supradiaphragmatic inferior vena cava (IVC) and the right atrium through the diaphragm from the abdominal cavity. Materials and Methods. The material of the anatomical study included 35 fresh cadavers. Several options of surgical access to the supradiaphragmatic IVC were successivel...

We present a resonant cavity approach for non-invasive, pulse-to-pulse, beam emittance measurements of non-circular multi-bunch beams. In a resonant cavity, desired field components can be enhanced up to π λ / L Q , where λ L Q is the loaded quality factor of the resonant mode λ , when the cavity resonant mode matches the bunch frequency of a bunch-train beam pulse. In particular, a quad-cavity...

We propose a new design of optical nanoantennas and numerically study their optical properties. The nanoantennas are composed of two cylindrical metal nanorods stacked vertically with a circular dielectric disk spacer. Simulation results show that when the dielectric disk is less than 5nm in thickness, such nanoantennas exhibit two types of resonances: one corresponding to antenna resonance, th...