A new type of lowpass filter with an ultra‐wide stopband, sharp transition and compact size is proposed. To reduce the circuit size, a bended transmission line is adopted in the stepped impedance resonators. To achieve a sharp roll‐off, a pendulum‐shaped resonator is implemented in the filter. The transition band is from 1.30 to 1.45 GHz with −3 and −20 dB, respectively. The stopband with an attenuation level better than 20 dB is from 1.45 up to 23.4 GHz, hence an ultra‐wide stopband with 18th‐harmonic suppression is achieved. Furthermore, the proposed filter exhibits an extremely small size of 0.09 λ _g × 0.11 λ _g where λ _g is the guided wavelength at the cutoff frequency.

The mammalian auditory system is able to process sounds over an extraordinarily large dynamic range, which makes it possible to extract information from very small changes both in sound amplitude and frequency. Evidently, response of the cochlea is essentially nonlinear, where it operates within Hopf bifurcation boundaries to maximize tuning and amplification. This paper presents a set of piecewise linear (PWL) and multiplierless piecewise linear (MLPWL1 and MLPWL2) active cochlear models, which mimic a range of behaviors, similar to the biological cochlea. These proposed models show similar dynamical characteristics of the Hopf equation for the active nonlinear artificial cochlea. Accordingly, a compact model structure is proposed upon which a 2-D cochlea is developed. The proposed models are investigated, in terms of their digital realization and hardware cost, targeting large scale implementation. Hardware synthesis and physical implementation on a FPGA show that the proposed models can reproduce precise active cochlea behaviors with higher performance and considerably lower computational costs in comparison with the original model. Results indicate that the MLPWL1 model has a lower computational overhead, precision, and hardware cost, while the PWL model has a higher precision and dynamically tracks the original model. On the other hand, the MLPWL2 model outperforms the others in terms of accuracy, dynamical tracking of the original model and implementation cost. The gain variations of the original, PWL, MLPWL1, and MLPWL2 models are 230, 100, 105, and 230 dB, respectively. The mean normalized root mean square errors (NRMSEs) of the PWL, MLPWL1, and MLPWL2 models are 0.11%, 11.97%, and 0.34%, respectively, as compared to the original cochlear model.

A compact wideband bandpass filter at the centre frequency of 5.77 GHz with 78% fractional bandwidth is presented. An especial coupling structure along with a novel triple mode spiral resonator designed based on modal analysis is used to provide a flat wide passband with excellent skirt characteristics. To verify the efficiency of the filter, a prototype is fabricated, tested and compared with some of the most recent works.

Based on the nonequilibrium Green’s function (NEGF) ballistic transport simulation, an optimized homojunction carbon nanotube (CNT) gate-all-around tunnel field effect transistor (GAA TFET) is proposed in this study. This TFET enhances the ON-state current and suppresses the ambipolarity extensively. By changing the channel diameter, gate length, and insulator thickness along with different values of doping levels and dielectrics of the source/channel/drain regions, a subthreshold swing $({SS})$ equal to ${11} ~\text {mV}/\text {dec}$ with an ON/OFF ratio of 10 ⁸ is obtained at ${V}_{G}={V}_{D}={0.4}$ V. Source (drain) underlap/overlap with the gate is also considered in reaching an optimum result. Such advantages can be followed on other 1-D TFET devices and are explained in detail on the energy band diagram of the device.

A wide-band band-pass filter (BPF) using coupled lines, rectangular stubs and Stepped-Impedance Resonators (SIRs) is presented in this paper. The proposed BPF operates over a large pass-band from 3.15 to 6.05 GHz covering 5G New Radio (NR) frequency Bands n77, n79 and 5G Wi-Fi, which includes the G band of US (3.3 to 4.2 GHz), 5G band of Japan (4.4 to 5 GHz) and 5G Wi-Fi (5.15 to 5.85 GHz). The presented filter has a maximum pass-band Insertion-Loss (IL) of 2 dB, a sharp roll-off rate and suppresses all the unwanted harmonics from 4.2 GHz up to 12 GHz with a 15 dB attenuation level. The performance of each section can be analyzed based on lumped-element circuit models. The electrical size of the BPF is 0.258 λ_g × 0.255 λ_g, where λ_gis the guided wavelength at the central frequency. The design accuracy is verified through implementing and testing the final BPF. The pass-band band-width can be controlled by adding the varactor diodes. A good relationship between the band-width and the varactor diodes are extracted by the curve fitting technique.