Analysis of the Reflection Properties in Electromagnetic Bandgap Coplanar Waveguides Loaded with Reactive Elements

Abstract

Abstract-In this work, we study the reflection properties of coplanar waveguides (CPW) periodically loaded with shunt connected capacitances and periodically perturbed by varying the slot width. These structures are of interest because the low pass frequency response with spurious frequency bands, inherent to the presence of capacitors, can be improved. This is achieved through the attenuation of frequency parasitics that is obtained by the introduction of slot width modulation. Both sinusoidal and square wave patterns are considered and the effects of the relative position of reactive elements with regard to the perturbation geometry is analysed. According to coupled mode theory, the central frequencies of the rejected bands in periodic transmission media are given by the spectrum of the perturbation function. However, it is demonstrated that, due to the presence of capacitors, multiple spurious bands can be simultaneously suppressed even in the case of a singly tuned (sinusoidal) perturbation geometry. This result points out that the frequency selective behaviour associated to the presence of slot width modulation can not be interpreted in the framework of coupled mode theory, since the rejection of spurious bands in periodic loaded CPWs is not merely given by the spectrum of the perturbation geometry.

Analytical Investigation of Periodic Coplanar Waveguides

“…All the dimensional parameters are normalized by the dimension of isolated CPW since the impedances are not dependent on (W + 2S). This can be seen in the expression of modulus k eo , k e1 , k o0 , and k o1 in (5), (13), (20), and (24), respectively. Figures 8 and 9 show the even-and odd-mode characteristic impedance of PCPW on top of GaAs (ε rb1 = 12.9).…”

“…For simplification and to investigate the properties of several parallel CPWs, a configuration called periodic coplanar waveguide (PCPW) with identical dimension in each periodic cell is a suitable model to analyze, as shown in Figure 1. It should be noted that this work is different from the periodic CPW structures in [20], which could be described as periodic loaded CPWs since the wave propagation properties are modified by periodically placed elements. The paper is structured as follows.…”

A Novel CPW Dual Passband Filter Using the Split-Modes of Loaded Stub Square Loop Resonators

“…In this paper, a novel CPW dual passband filter is designed by using the split-modes of the loaded stub square loop resonators. CPW has been taken more and more attention for its advantages such as easy connections in series and shunt without via hole, insensitivity to substrate thickness, and low dispersion effect in the designed of microwave and millimeter wave circuits [7,8]. By loading an open stub in the proposed CPW square loop resonator, two degenerated modes could be simultaneously excited and they are split to produce two resonance frequencies.…”

Equivalent Graphical Solutions of Terminated Conjugately Characteristic-Impedance Transmission Lines With Non-Negative and Corresponding Negative Characteristic Resistances

“…In addition, graphical solutions based on the standard T-chart and the extended T-chart of these specific examples are employed to confirm that both CCITL models are equivalent. Figure 2 illustrates a finite periodic TL structure implemented by a multi-section transmission line (MSTL) of coplanar waveguides (CPW) [19,20]. An MSTL with a three-section CPW is analyzed and designed using the Agilent Genesys EDA software [21].…”