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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]

Microwave components with nonlinear phase responses are developed using a simplified composite right/left-handed (CRLH) transmission-line (TL) structure without the series capacitance or the shunt inductance. Using such a simplified CRLH structure, arbitrarily dual-band microstrip components have been realized in compact sizes such as a quarter-wavelength short-circuited stub and dual-band branch-line couplers. Simulation and measurement results are given to demonstrate the efficiency and good performance of the proposed components. For the quarter-wavelength short-circuited stub based on the simplified CRLH-TL structure without the series capacitance, it has been shown that the insertion loss is less than -0.1 dB. For the arbitrarily dual-band branch-line coupler, experiment results exhibit that $21 and $31 are larger than -3.6 dB, the isolations are smaller than -30 dB, the return losses are smaller than -20 dB, and the phase differences are within 90° ± 1.8°. [ABSTRACT FROM AUTHOR]