We carried out 20×12.5Gbit/s optical mode group division multiplexing communication using a plastic optical fiber in the order of meters at 1.55µm. We split lower-order and higher-order propagation modes of a graded-index plastic fiber in two groups and assigned these groups with different communication signal channels. The two mode groups were excited with a fan-in/fan-out device developed for optical space division multiplexing communication using a silica optical fiber and were demultiplexed with optical-domain spatial filtering. Obtained bit error rates of all the demultiplexed signals were below the 7% overhead hard-decision FEC threshold (3.8×10^-3).

For the simulation or theoretical analysis of reverberation chambers, the conductivity of the chamber wall is commonly used when modeling a reverberation chamber, which is one of the focal points of concern for the electromagnetic compatibility community. If the conductivity is not properly set, the field level formed within a chamber will be different from what is expected. The conductivity can be used to estimate the quality factor. Therefore, we get the appropriate equivalent conductivity by comparing numerical results and experimental results of quality factor. To reduce the dependence on the frequency and the dimensions of a chamber, we proposed an intermediate parameter α-based setting for the conductivity, i.e., 10kS/m for α<40, 40kS/m for 40<α<80, and α>80 for 100kS/m. The numerical results of the quality factor have been verified by the measurement performed within two reverberation chambers. It is expected that the proposed conductivity setting in terms of α will be a useful way for the simulation or theoretical analysis of reverberation chambers.

With the continuous development of new energy generation and power electronics technology, Virtual Synchronous Generator (VSG) technology has been widely applied. VSG technology achieves power exchange between the DC side and the system by controlling the inverter. Traditional VSG control strategies suffer from issues such as long transient adjustment times, poor stability, and steady-state deviations. To address these challenges, this paper proposes an adaptive parameter control strategy for a virtual synchronous generator with transient damping characteristics. Initially, transient damping is introduced on the basis of the traditional constant damping strategy to eliminate the steady-state error during the primary frequency control of the system under grid frequency fluctuations. Subsequently, an analysis is conducted on the dynamic behavior of the VSG by examining the trends in variations of its rotational inertia and damping coefficients under system oscillations, an inertia damping adaptive control strategy is proposed. Finally, a simulation model of the system is constructed using MATLAB/Simulink, and this control strategy is compared with existing strategies through simulation. The results demonstrate that this control strategy enhances the transient performance of the VSG system, improves system stability, and reduces steady-state errors.

This study presents the transmission of electromagnetic waves through a partially covered narrow slot on a thick conducting screen when a plane wave is incident on the slot. The slot in the thick plate that creates a waveguide structure mainly causes resonance transmission (RT) above the cutoff; moreover, a weak RT (WRT) phenomenon also occurs. However, the WRT phenomenon has not been considered. In contrast, a partially covered slot in a thick plate creates a partially slotted waveguide (PSW). In the PSW structure, when the slot length is below the half-wavelength, WRT mainly occurs, even if the waveguide is above the cutoff, and RT does not occur. The amplitude of this WRT depends on the length of the slot and plate thickness. In addition, the transmission cross section (TCS) patterns with symmetry and asymmetry are presented with resonance states to consider the transmission mode in more detail.

A dual-mode wide tuning range voltage-controlled oscillator (VCO) based on switchable weakly coupled cores is presented in this paper. The dual-mode operation is achieved when the two switched VCO cores are under ON and OFF states. A weakly coupled transformer with small coupling coefficient of the two-coupled LC tanks of two VCO cores is used to ensure that the VCO works at desired frequency under both modes. The results show that large coupling coefficient between the LC tank of two VCOs and LC tank of buffer enhances the quality factor of the VCO’s LC tank at lower resonant frequency under both modes. Fabricated in a 55nm CMOS process, the VCO covers the frequency tuning range from 22.3 to 27.1GHz and from 31.2 to 36.6GHz when the switched VCO is under ON or OFF state, respectively. The dual-mode VCO achieves a phase noise of -127.6dBc/Hz at 10MHz offset for 22.3GHz carrier frequency.

This letter presents a fully monolithic microwave integrated circuit (MMIC) switched filter banks (SFBs) that feature a digitally selectable operation bandwidth frequency. The integrated SFBs with four independently controlled channels span the 2GHz to 12GHz frequency range. Unlike the existing methods, the proposed SFB consists of a pair of single-pole four-throw (SP4T) switches coupled with four band-pass filters (BPFs), and the TTL signal can directly drive the SFB through an inner integrated FET-driven circuit, achieving facility usage in the RF system. For verification, two wideband SFB MMICs were designed and fabricated using a 0.25-µm gallium arsenide (GaAs) based InGaAs pHEMT Enhancement/Depletion-Mode Device (E/D-Mode) process, named the low-band SFB and high-band SFB. Measurement results show that the minimum insertion losses for the four channels of the proposed low-band MMIC SFB are around 4.6 to 6.3dB. The measured Rectangle factor SF_30dB for the four channels are all below 1.87. The measured minimum insertion losses are around 4.9 to 6.1dB for the high-band SFB. The measured Rectangle factor SF_30dB for the four channels are still bellow 2.15. The proposed SFB MMIC shows remarkable selectivity and high integration.

Vision chip plays an important role in artificial intelligence (AI) image processing. In-imager global-parallel processing architecture (IIGP) demonstrates considerable promise for ultralow latency at both circuit and system levels towards vision chips that demand high processing speed. However, functionality such as edge detection of previous IIGP work is limited because of the bottleneck of processing multibit precision multiplication and accumulation operations (MACs) in a binary architecture. To address this bottleneck, this paper proposed a 32×32 pixels ultrahigh framerate vision chip that features central-based edge detection (CBED) processed by the all-digital IIGP architecture. The SPICE simulation results show that the proposed circuit achieves an ultrahigh framerate of 5.56Mfps, which is 2.16× compared to the state-of-the-art in/near-imager vision chip work when processing edge detection functionality, marking a significant advancement in high-speed image processing.

Bistatic radar has the characteristics of wide detection range and large transmission distance, but partial characteristics of bistatic scattering at the three-dimensional dynamic sea surface still need further research and validation. A facet electromagnetic model is proposed in this paper to calculate the bistatic electromagnetic scattering from the 3-Dimensional (3-D) time-evolving sea surface. In the simulation, the result shows that the Advanced Integral Equation Method (AIEM) algorithm is more accurate than the Integral Equation Method (IEM) algorithm. Based on this facet-based method, the sea clutter from 3-D time-evolving sea surface can be acquired. The Doppler spectra are calculated and found that the Doppler spectrum becomes wider with the increase of the wind speed.

This paper proposes a self-powered multiple piezoelectric (multi-PZTs) energy harvesting interface based on extensible parallel synchronized switching harvesting on inductor (PSSHI) rectification with power region optimization technique. The extensible PSSHI rectifier can accept multi-PZTs voltages input with arbitrary phase, thus addressing the charge conflict problem. The power region optimizer can assist the rectifier to operate within the high output power region. Meanwhile, all active devices in the circuit are powered by the harvested energy. Finally, the experimental results show that the average charging power of the circuit is 559.8µW, and the energy conversion efficiency is 80.7%. Compared with the extensible PSSHI rectifier without power region optimization, the average charging power in this circuit is increased by 94%. Additionally, the experimental tests indicate that the interface circuit can completely realize cold start and self-power supply.

This paper proposes the concept of a complex maximum power point tracking (MPPT) circuit for adaptive conjugate impedance matching of wireless power transfer. The proposed circuit consists of an orthogonal power distribution circuit using quadrature hybrid and two rectifier circuits and DC-DC converters. By controlling the input impedance of two DC-DC converters, the complex impedance of RF input can be varied to satisfy complex conjugate matching. This circuit enables high-power and high-frequency handling for matching circuits because no variable device is used in the RF region, and control is done in the DC region. Measurements at 433MHz confirm that complex impedance in the RF region can be controlled by adjusting the two real impedances.