Presented is a structure to design a compact ultra-wideband (UWB) bandpass filter (BPF) with excellent selectivity that enables inclusion of notch-band characteristics within the filter's passband to mitigate interfering signals that coexist within the UWB spectrum. The proposed filter topology utilises two signal paths with different electrical lengths made up of two wideband BPFs that are connected in parallel. The mechanism of generating notch-band is delineated based on transversal signal-interaction concepts. Good agreement is observed between simulated and measured performances of the UWB filter, demonstrating a fractional bandwidth of 123% (2.66-11.2 GHz) with a sharp notch-band at 5.21 GHz.

The push to advance efficient, renewable, and clean energy sources has brought with it an effort to generate materials that are capable of storing hydrogen. Metal-organic framework materials (MOFs) have been the focus of many such studies as they are categorized for their large internal surface areas. We have addressed one of the major shortcomings of MOFs (their processibility) by creating and 3D printing a composite of acrylonitrile butadiene styrene (ABS) and MOF-5, a prototypical MOF, which is often used to benchmark H 2 uptake capacity of other MOFs. The ABS-MOF-5 composites can be printed at MOF-5 compositions of 10% and below. Other physical and mechanical properties of the polymer (glass transition temperature, stress and strain at the breaking point, and Young's modulus) either remain unchanged or show some degree of hardening due to the interaction between the polymer and the MOF. We do observe some MOF-5 degradation through the blending process, likely due to the ambient humidity through the purification and solvent casting steps. Even with this degradation, the MOF still retains some of its ability to uptake H 2 , seen in the ability of the composite to uptake more H 2 than the pure polymer. The experiments and results described here represent a significant first step toward 3D printing MOF-5-based materials for H 2 storage. 3

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Due to a recent growth in three-dimension (3D) printing technology, engineers can fabricate affordable and versatile antennas; however, lossy conductive materials, inadequate antenna terminations, and simplistic designs which do not adequately utilize the available volume continue to limit the capabilities of 3D printed antennas. In this work, the dielectric constants of three polylactic acid (PLA) materials, dielectric PLA, magnetic PLA and conductive PLA, were measured using the coaxial transmission line method, and the results were compared with measurements using the commercially available coaxial probe method. Based on published dielectric constants for solid non-printed PLA, a variety of antenna designs were simulated and fabricated. Each of these antenna designs addressed a certain shortcoming faced by 3D printed antennas. The antennas were designed with a target resonant frequency of 2.45 GHz, an impedance bandwidth of at least 500 MHz, and a gain greater than 1.5 dBi. The three antennas presented here are a fractal bow-tie antenna (FBTA), a spiral antenna, and a Yagi-Uda antenna.