Electromagnetic Metamaterials: Transmission Line Theory and Microwave Applications. By Christophe Caloz and Tatsuo Itoh.

Ordinary differential equations of the first order linear differential equations complex numbers and linear algebra simultaneous linear differential equations numerical methods the descriptive theory of nonlinear differential equations mechanical systems and electric circuits Fourier series Fourier integrals and Fourier transforms the Laplace transformation partial differential equations Bessel functions and Legendre polynomials applications and further properties of matrices vector analysis the calculus of variations analytic functions of a complex variable infinite series in the complex plane the theory of residues conformal mapping.

Advanced Engineering Mathematics. By C. R. Wylie. Pp. xiv, 813. 1966. (McGraw-Hill.)

In recent years, the dielectric resonator antenna (DRA) has emerged as a new and viable alternative to conventional low-gain elements such as dipoles, monopoles, and microstrip patches. This practical resource presents complete, up-to-date details on DRAs in a single volume. The book provides you with clear guidance on the mode of operation and radiation behavior of DRAs, the main methods of excitation, and the major advances in DRA technology. This hands-on reference equips you with simple equations and graphs that help you rapidly design DRAs of spherical, cylindrical, and rectangular shapes, without having to resort to complex analytical or numerical calculations. You find guidelines for designing feeds required to excite the DRAs, such as probes, apertures, and microstrip lines. In addition, the book offers you various techniques for enhancing the bandwidth performance of DRAs for wideband applications. You learn how to design low profile DRAs and DRAs with circular polarization. Several approaches for designing linear and planar DRAs arrays are also considered. Moreover, this comprehensive book provides advice on the fabrication of DRAs and measurement methods used to characterize their performance. Numerous design examples are included to give you a sense of the versatility that DRAs afford.

Dielectric resonator antenna handbook

This chapter is focused on circularly polarized antennas. Key definitions and governing equations of circular polarization are given. Infinitesimal dipole sources are considered to establish circularly polarized radiation. First, radiation patterns of cross dipoles are mathematically reviewed, from which the condition of circularly polarized waves is concluded. Later, the idea is extended to four displaced sequentially rotated dipole antennas, resulting in circularly polarized waves within a wide angular range in space. The extension of the concept to the magnetic source counterparts and Huygens sources is briefly discussed. Other than point sources, also known as one-dimensional current sources, sources of circularly polarized radiation are further investigated for two-dimensional cases, such as microstrip patch antennas, and threedimensional structures, such as volumetric current sources existing in dielectric resonator antennas. For these cases, the creation of circularly polarized radiation using single-feed and dual-feed, perturbed structures and sequentially rotated method is described. As a design example, numerical andmeasurement results of circularly polarized square patch ring antennas are extensively discussed and presented in this chapter. The square-ring microstrip antenna is selected as it closely approximates the sequentially rotated currents, and also it has not been widely studied in the literature.

Circularly Polarized Antennas

The goal of this study is to improve the bandwidth of a miniaturized antenna. The proposed technique combines a slot antenna and a dielectric resonator antenna (DRA) to effectively double the available bandwidth without compromising miniaturization or efficiency. With proper design it is observed that the resonance of the slot and that of the dielectric structure itself may be merged to achieve extremely wide bandwidth over which the antenna polarization and radiation pattern are preserved. In addition, using the DRA, a volumetric source, improves the radiation power factor of the radiating slot. A miniaturized antenna figure of merit (MAFM) is defined to simultaneously quantify aspects of miniaturized antenna performance including the degree of miniaturization, efficiency, and bandwidth. Figures for various common types of antennas are given and compared with that of the proposed structures. In order to determine the effects of varying design parameters on bandwidth and matching, sensitivity analysis is carried out using the finite-difference time-domain method. Numerous designs for miniaturized slot-fed dielectric resonator antennas are simulated and bandwidths exceeding 25% are achieved. Two 2.4 GHz antennas are built, characterized, and the results compared with theory.

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Compact slot and dielectric resonator antenna with dual-resonance, broadband characteristics

In this paper, two single fed low-profile cavity-backed planar slot antennas for circular polarization (CP) applications are first introduced by half mode substrate integrated waveguide (HMSIW) technique. One of the structures presents right handed CP (RHCP), while the other one offers left handed CP (LHCP). A single layer of low cost printed circuit board (PCB) is employed for both antennas providing low-cost, lightweight, and also easy integration with planar circuits. An inset microstrip line is used to excite two orthogonal quarter-wave length patch modes with required phase difference for generating CP wave. The new proposed antennas are successfully designed and fabricated. Measured results are in good agreement with those obtained by numerical investigation using HFSS. Results exhibit that both antennas present the advantages of conventional cavity backed antennas including high gain and high front to back ratio (FTBR).

Development of a Low-Profile Circularly Polarized Cavity-Backed Antenna Using HMSIW Technique

Two low-profile hybrid antennas are presented. One of the structures provides linearly polarized (LP) wave and the other one produces circularly polarized (CP) radiated field. half-mode substrate integrated waveguide (HMSIW) technique is used to make a semi-circular cavity for reducing the antenna size. Using proximity effect, TM010 mode of a rectangular patch is excited by the HMSIW cavity. An inset microstrip line is used to excite the structure which leads to capability of planar circuit integration. The effects of the HMSIW cavity-backed antenna with and without patches are investigated. The simulated results show that adding the patch increases bandwidth and improves antenna gain. Both proposed hybrid antennas are made on a single-layer substrate using printed circuit board (PCB) process. Two prototypes of the proposed antennas are designed, simulated and fabricated. It is shown that broadband impedance bandwidth of 10% and maximum gain of 7.5 dBi is obtained for the LP antenna. In the case of CP antenna, axial ratio (AR) bandwidth is at least 1% with maximum gain of 6.8 dBi. The proposed hybrid antennas are low profile and offer attractive features such as high gain, low cross polarization level and high front-to-back ratio.

Development of Low-Profile Patch and Semi-Circular SIW Cavity Hybrid Antennas

A miniaturized frequency-scanning leaky-wave antenna (LWA) with circular polarization (CP) and backward-broadside-forward radiation is presented. Half-mode substrate integrated waveguide (HMSIW) in combination with interdigital capacitors (IDCs) is utilized in order to achieve a composite right/left-handed leaky-wave structure. Ramp-shaped slots are introduced as interdigital capacitors. Using this structure, the balanced condition (in which series and shunt resonances are equal) can be obtained for the unit-cell. As a result, wide bandwidth of 7.4-13.5 GHz with continuous angular scanning of ~ -70° to 70 ° is achieved. The axial ratio in the direction of the main beam is lower than 3.1. The performance of the antenna is measured, and close agreement between the simulation and measurement is observed.

A HMSIW Circularly Polarized Leaky-Wave Antenna With Backward, Broadside, and Forward Radiation

In this letter, a novel scheme for linear polarized cavity-backed antennas is introduced. In this design, for the first time, half-mode substrate integrated waveguide (HMSIW) technique is used to create a radiating aperture rather than minimizing the structure. The proposed antenna has the advantages of compactness, low profile, light weight, low fabrication cost, and easy integration with planar circuits. It also can be easily implemented by using only a single layer of printed circuit board (PCB). The proposed antenna is numerically investigated using HFSS. A sample antenna is fabricated, and its radiation characteristics are measured. The radiation patterns of the proposed antenna are also calculated based on the aperture antennas theory. Good agreement among calculated, simulation, and measured results is observed. The measured results show that the proposed antenna has also the advantages of conventional cavity-backed antennas including high gain, low cross-polarization level (CPL), and high front-to-back ratio (FTBR).

Development of a Linearly Polarized Cavity-Backed Antenna Using HMSIW Technique

This paper presents the design of a dual stacked microstrip antenna over the frequency range of 9.5–16 GHz. Investigations show that in the new structure the impedance bandwidth of the antenna is increased to 44% and the thickness of the antenna decreases to 0.14λ. Furthermore, the gain bandwidth of the antenna (above 8 dB) is increased to 5.1 GHz (40%).

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Mohammad Hassan Neshati

Papers

Development of a Low-Profile Circularly Polarized Cavity-Backed Antenna Using HMSIW Technique

Development of Low-Profile Patch and Semi-Circular SIW Cavity Hybrid Antennas

A HMSIW Circularly Polarized Leaky-Wave Antenna With Backward, Broadside, and Forward Radiation

Development of a Linearly Polarized Cavity-Backed Antenna Using HMSIW Technique

A high gain dual stacked aperture coupled microstrip antenna for wideband applications