Compact tunable U-Hi-Lo low pass filter using quasi C-shaped stubs

Abstract

This paper introduces a tunable U-form low pass filter composed of Hi-Lo impedance lines with a pair of quasi C-shaped inductors for covering L-band, S-band, and C-band. The quasi- C-shaped inductors are integrated for the purpose of widening pass-band, minimizing the insertion loss, and improving the roll-off rate. The constructed topology has been printed on RO4003 with permittivity of 3.38, loss tangent of 0.0027, and height of 0.813 mm. The filter is distinguished with a compact size of 15.5 × 10.5 mm2, in addition to its low insertion loss of 0.6 dB in L-band and S-band, sharpness factor of 28.8 dB/GHz, and -20 dB stop-band of 4.85 GHz. A pair of lumped capacitors are both embedded in the substrate between the open ends of the C-shaped inductors and the ground plane for achieving a tuning range from 4.7 GHz till 7.56 GHz when using 0.2 pF lumped capacitors. Consequently, it will lead to a reduction in size of 37.5 % when compared to the size of the conventional LPF. Good consistency between simulated and measured characteristics of the fabricated LPF is achieved with/without lumped capacitors.

A novel tropoelastin-based resorbable surgical mesh for pelvic organ prolapse repair

“…A dedicated electrospinning system (ES) [ 26 ] was used to fabricate continuous yarns consisting of four different blends of the natural protein tropoelastin and the synthetic polymer polycaprolactone (PCL). A schematic representation of the electrospinning setup is shown in Supp.…”

“…The 75:25, 50:50 and 25:75 tropoelastin:PCL yarns contained fibers that were 618 ± 144 nm, 541 ± 70 nm and 645 ± 75 nm wide, respectively. Larger twist angles contribute to increased flexibility and tensile strength [ 26 ]. Average fiber twist angles ( Fig.…”

“…A purpose-built modified dual spinneret electrospinning system based on Ali et al. [ 26 ], combination with parameters that we had defined previously for the fabrication of tropoelastin:silk hybrid yarns [ 24 ], were used in this study. The electrospinning system was housed inside a poly (methyl methacrylate) (PMMA) box and the temperature was kept constant at 20 °C.…”

“…The process is scalable as evidenced by commercial electrospinning companies that provide contract manufacturing [ 25 ]. To improve the surgical applicability of electrospun biomaterials, the traditional method can be modified to derive a continuous yarn [ 26 ] comprising aligned fibers that form a twist, which increases tensile strength and flexibility of the yarn. These continuous yarns are capable of being woven into more complex structures and possess the ability to withstand mechanical stress as needed to support load-bearing tissues in the body [ 26 , 27 ], an important consideration for vaginal repair.…”