M. E. de Cos

Design of Planar Artificial Magnetic Conductor Ground Plane Using Frequency-Selective Surfaces for Frequencies Below 1 GHz

A novel design of planar artificial magnetic conductor (AMC) based on a frequency-selective surface (FSS) for frequencies below 1 GHz is presented. A discussion about design parameters and the influence of dielectric substrate permittivity in the operating band and the operating bandwidth is presented. The discussion is supported by a finite element method (FEM) simulation.

Novel SHF-Band Uniplanar Artificial Magnetic Conductor

The design of a novel SHF-band uniplanar artificial magnetic conductor (AMC) is presented. A prototype is manufactured and characterized based on reflection coefficient phase. The designed prototype shows broad AMC operation bandwidth and polarization angle independency. Its angular margin when operating under oblique incidence is also tested. The results are supported by finite element method (FEM) simulations and measurements in an anechoic chamber.

Microstrip Patch Antenna Bandwidth Enhancement Using AMC/EBG Structures

A microstrip patch antenna with bandwidth enhancement by means of artificial magnetic conductor (AMC)/electromagnetic band-gap structure (EGB) is presented. The electrical characteristics of the embedded structure are evaluated using MoM simulations. The manufactured prototypes are characterized in terms of return loss, gain, and radiation pattern measurements in an anechoic chamber.

Novel Broadband Artificial Magnetic Conductor With Hexagonal Unit Cell

The characteristics of a novel broadband artificial magnetic conductor (AMC) design based on a unilayer FSS with hexagonal unit cells and without via-holes are presented by means of FEM simulations and measurements in an anechoic chamber. A comparison between this novel design and other well-known designs is carried out in terms of AMC operation bandwidth. The designed structure shows polarization-angle independence, and its angular stability under oblique incidence is also analyzed based on measurements.

Novel Miniaturized Artificial Magnetic Conductor

The design of a novel miniaturized artificial magnetic conductor (AMC) using interdigital capacitors is presented. The operation of the AMC is evaluated using finite element method (FEM) simulations. A prototype is manufactured and characterized based on reflection coefficient phase in an anechoic chamber. The performance of the AMC unit cell for both normal and oblique incidence is also studied.

Dual-Band Uniplanar CPW-Fed Monopole/EBG Combination With Bandwidth Enhancement

A novel low-profile uniplanar dual band coplanar waveguide (CPW)-fed monopole antenna/electromagnetic band-gap (EBG) combination, exhibiting bandwidth enhancement, is presented. Prototypes of the monopole antenna alone and combined with the EBG in the same layer are manufactured using laser micromachining. The characterization results of the manufactured prototypes in terms of return loss and radiation pattern measurements in an anechoic chamber are shown for comparison.

Dual-Band Antenna/AMC Combination for RFID

A novel antenna/Artificial Magnetic Conductor (AMC) combination usable in dual-band Radio Frequency Identification (RFID) tags over metallic objects is presented. A compact and low thickness prototype is manufactured and characterized in terms of return loss and radiation properties in an anechoic chamber both alone and on a metallic plate. The performance exhibited by the presented antenna/AMC prototype is proper for RFID tags on both metallic and nonmetallic objects.

Facing the angular stabilization of loop-based artificial magnetic conductors through lumped inductors

This work focuses in achieving the angular stabilization of a square loop-based AMC from a novel approach: by exploring the possibilities of introducing lumped inductors. The study is conducted considering the typical constraints an actual designer has to cope with (concerning limited size and dielectric thickness and properties). As a result, a stable AMC in the 5.8GHz band is obtained, meeting the design requirements. Due to its effectiveness, the novel developed methodology can be directly extended to enhance the angular stability of any loop-based AMC, wide spreading their applications.

High-Performance Computational Electromagnetic Methods Applied to the Design of Patch Antenna with EBG Structure

In this contribution High-Performance Computing electromagnetic methods are applied to the design of a patch antenna combined with EBG structure in order to obtain bandwidth enhancement. The electrical characteristics of the embedded structure (patch antenna surrounded by EBG unit cells) are evaluated by means of method of moment technique (MoM) whereas for designing the unit cell, the finite element method (FEM) together with the Bloch-Floquet theory is used. The manufactured prototypes are characterized in terms of return loss and radiation pattern in an anechoic chamber.

Reply to “Comments on “Novel Broadband Artificial Magnetic Conductor With Hexagonal Unit Cell””

The authors are thankful for the useful comments [1] on their letter [2]. The presented artificial magnetic conductor (AMC) is not composed of square but hexagonal unit cells. The referenced first paragraph of [2, Section II], “Planar AMC Design,” makes reference to a general behavior based on a very simple LC model for the unit-cell geometry. Generally, the unit cell can be considered a frequency selective surface (FSS) backed by a dielectric slab with metallic ground plane. To increase the bandwidth of an AMC, it is necessary to reduce the total capacitance C. When the distance between unit cells increases, the gap capacitance decreases. If this is the main capacitive element contributing to the total C, the bandwidth increases. This happens, for example, for the patch unit cell in [3, Table I], a work referenced by [1]. In [3], only one capacitive element is used to model the unit cell, and the objective is to maximize the bandwidth while preserving the resonance frequency. The point is that the total C of the unit-cell model has to be expressed as a series or parallel combination of capacitive elements (gap, parallel plates, fringing effects, etc.), which obviously depends on the geometry of such a unit cell. However, the geometry of the presented unit cell (formed by dipoles) is mainly inductive due to the narrow strips. The behavior of the presented unit cell is described in the third paragraph of [2, p. 616]. It is clearly mentioned that there are two main capacitive elements that contribute to the total C: coplanar C (or gap C) and parallel plates C. Moreover, it is stated that “in sum, the wider AMC operation bandwidth for smaller unit-cell size (W) of this novel design is due to both slightly increased L and more significantly C decreased values of the parallel LC equivalent circuit.” This does not contradict [1] since, according to Fig. 3 and Table I of [2], for smaller unit cell W, the distance between cells 2d (the gap) decreases, and so the gap capacitance.