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A broadband microstrip-to-waveguide end-wall probe transition using a semicircular loop is proposed in this letter. The simulated 20-dB fractional bandwidth for this transition is 48.3% which could cover the whole Ka-band. Then, a compact broadband waveguide termination is developed by combination of this microstrip-to-waveguide transition and a 50Ω microstrip termination. To reduce parasitic effects, the microstrip termination is grounded by a microstrip radial stub. The fabricated waveguide termination shows a compact size and has a return loss better than 16.6 dB from 26 to 40.8GHz. [ABSTRACT FROM AUTHOR]

In this paper, a Ka-band wideband filter with a reconfigurable mode of bandpass-bandstop switching is presented. As a low-Q resonator, a rectangle ring with a straight "tail" is inserted into the central E-plane of a waveguide to realize the wideband performance. With the "ON" or "OFF" state of the PIN diode, the EM field driving by the resonator may be the same direction with or suppress the TE10 of the waveguide, which makes the filter be reconfigurable. At the frequency of 33GHz-37GHz, the insertion loss is lower than 1 dB at band-pass mode, and when it is working as a band-stop filter, the insertion loss is more than 15 dB on the whole frequency band. [ABSTRACT FROM AUTHOR]

In this paper, a new substrate integrated waveguide (SIW), which is called reconfigurable substrate integrated waveguide (RCSIW) is proposed. RCSIW is derived from SIW and tunable technology which is widely used in microwave system. It is realized by replacing the side-wall metal posts of SIW with several grounded varactors which are employed to make the SIW tunable. The cutoff frequency and propagation constant can be reconfigurable by controlling these varactors. A RCSIW is designed to test these properties with the input and output of microstrip line. Ansoft HFSS was used to get the characteristics of RCSIW. The results show the reconfiguration of RCSIW. [ABSTRACT FROM AUTHOR]

We create an invisible gateway simply by putting electric and magnetic superscatterers in a metallic waveguide. The characteristics of the electric and magnetic resonators are analyzed in a metallic hollow waveguide, and the dual-mode superscattering property is discussed in detail to broaden the bandwidth of the invisible gateway. Good agreement is achieved between the simulation and measurement for such an invisible gateway. The present work help readers understand easily how an invisible gateway works (or makes sense) in a classical way without using any complex metamaterial or complicated method of transformation optics. [ABSTRACT FROM AUTHOR]

An efficient method is presented to design the evanescent wave amplification exactly by cascading two layers of periodic series-shunt capacitors and inductors, which simulate a bilayer of magnetic and electric plasmas. Based on the presented method, equivalent lumped parameters of circuit structures are retrieved, from which the evanescent-wave amplification (EWA) is obtained at a designed frequency. Full-wave simulations show that the relative offset of the EWA frequency is less than 0.1%. The structure has been fabricated and measured, and the measurement results have good agreements with the simulation results. The proposed method can be used to design other periodic circuit structures, and the exact design of EWA can be used in the fabrication of novel components. © Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1870–1873, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23501 [ABSTRACT FROM AUTHOR]

This paper presents a novel compact meta-structure, which is characterized by left-handed properties. In the novel structure, two linear arrays of metallic vias and short-stub inductors are used to generate shunt inductors besides the series interdigital capacitors. Compared with conventional composite right/left-handed transmission-line structures, the new structure has weaker coupling to other components and is easily controlled by adjusting the shunt inductance and series capacitance to produce different left-handed properties. Due to the isolation of two via arrays, the proposed structure can also be transplanted directly from the microstrip system to the coplanar-waveguide system. We have proposed an efficient procedure to retrieve the equivalent propagating modes for both forward and backward waves based on the matrix pencil method, which provides an easy way to study the propagation characteristics. Using such a meta-structure, a series of super-wide bandpass filters are designed and fabricated at different frequency bands. Good agreements between simulation and experiment results have been achieved, and good performance in passbands and stopbands has been observed with a relative 3-dB bandwidth larger than 70%. For easy design of such super-wide bandpass filters, an experienced formula is given between the physical size and the center frequency of the 3-dB passband, which can be used to redesign any filters at other frequency bands. [ABSTRACT FROM AUTHOR]

Surface plasmon can lead to wave propagation not only along the surface as a dielectric waveguide but also in the normal direction to the surface because of the evanescent-wave amplification by metamaterial. In this letter, the authors design a surface plasmon structure to implement the electric and magnetic plasma resonances in microwave regime. Near the plasma resonant frequency, they directly observe the strong surface plasmon by experiments. The evanescent waves can be transmitted in an exponentially increasing and decreasing distribution, which is the evanescent-mode propagation by the tunneling effect. [ABSTRACT FROM AUTHOR]