a fourth-degree substrate integrated waveguide (siw) crossed coupled band pass filter for wlan band is designed by using a new negative coupling structure. it consists of two u shape microstrip lines on top and bottom planes with via holes at the center of them. this paper investigates the phase characteristics of negative and positive coupling structures and their effects. the design, fabricat...

A fourth-degree Substrate Integrated Waveguide (SIW) crossed coupled band pass filter for WLAN band is designed by using a new negative coupling structure. It consists of two U shape microstrip lines on top and bottom planes with via holes at the center of them. This paper investigates the phase characteristics of negative and positive coupling structures and their effects. The design, fabricat...

Abstract In this paper, we discuss asymptotically flat and anti-de Sitter (AdS) boson star in $$(4+1)$$ ( 4 + 1 ) -dimensional Gauss–Bonnet gravity. We describe the dependence of mass, charge radius on model parameters,...

In this study, Polyaniline molecule (emeraldine base) is modeled as a molecular wire and the effects of the metal/molecule coupling strength and the molecule length on the current-voltage (I-V) characteristics are numerically investigated. Using a tight-binding Hamiltonian model, the methods based on Non-equilibrium Green’s function theory, Landauer formalism and Newns-Anderson model, our calcu...

We consider coupled lasers, where the intensity deviations from the steady state, modulate the pump of the other lasers. Most of our results are for two lasers where the coupling constants are of opposite sign. This leads to a Hopf bifurcation to periodic output for weak coupling. As the magnitude of the coupling constants is increased (negatively) we observe novel amplitude effects such as a w...

In this talk I review my recent work with Brian Greene and Thomas Roos . First I discuss the effect of a negative cross-coupling on the inflaton decay in two scalar field theories. Our main finding is a new effect, the negative coupling instability, which leads to explosive particle production and very fast inflaton decay. Then I discuss the consequences of this instability for grandunified bar...