F. P. Casares-Miranda

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A novel high-gain active composite right/left-handed (CRLH) metamaterial leaky-wave antenna (LWA) is presented. This antenna, which is designed to operate at broadside, is constituted by passive CRLH leaky-wave sections interconnected by amplifiers, which regenerate the power progressively leaked out of the structure in the radiation process in order to(More)
Interdigital capacitors (IDCs) are convenient capacitance devices in microstrip circuits, even if only low capacitance values can be achieved. Nevertheless, undesired resonances degrade their performance when frequency increases. Short circuits across the end of alternate fingers of the IDC improve its high frequency response by eliminating that drawback.(More)
A novel broadband (including dc) microstrip-to-microstrip vertical transition for multilayer microwave circuits is proposed. This transition solves the problem of the discontinuity typically appearing in via hole transitions between two microstrip transmission lines in different layers. An analogy existing between this transition and a rectangular coaxial(More)
An enhanced composite right/left-handed (CRLH) transmission line (TL) is presented in this letter. This TL, designed in microstrip technology, is implemented by means of a new improved interdigital capacitor (IDC), the so-called wire bonded IDC (WBIDC). The use of the WBIDC broadens the frequency band where the CRLH TL can be considered as a TL. A(More)
The wire-bonded interdigital capacitor (WBIDC) is an interdigital capacitor with short circuits across the end of alternate fingers that result in an improved frequency response. This paper presents the analytical and circuital models of the WBIDC, which are useful to design and to incorporate into an electromagnetic or circuit analysis computer-aided(More)
In this paper, the exact model of a multiconductor transmission line with bonding wires is presented. The model is based on the multiport admittance matrix, and is valid for any number of conductors in the structure. The model shows how to compute the two-port admittance matrix of the wire-bonded structure with direct application to the wire-bonded(More)
Active microwave metamaterial (MTM) structures, in particular composite right/left-handed (CRLH) transmission line (TL) MTM structures, are introduced in a general scope. Several planar implementations are described. A dual-band distributed amplifier (DA) and a high-gain leaky-wave antenna (LWA) are presented as illustrations of guided-wave and(More)
A high-gain active CRLH LWA has been presented. Different modifications in the layout of the microstrip CRLH LW structure most commonly used up to now have been proposed. A remarkable reduction in the cross-polar component, increasing the XPD in more than 28 dB, and a beam forming from fan-beam to pencil-beam radiation pattern have been demonstrated. By(More)
The assessment of an alternative six-port circuit in terms of frequency behavior when used to measure complex voltage ratio is presented. A numerical comparison to commonly used and well-known six-port circuits is carried out. The presented results can help us to choose between different six-port configurations depending on the application, and show that(More)
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