A frequency-reconfigurable slot-ring antenna switching between L- and C-bands is presented. The aperture of an L-band can be reconfigured to a 2 × C -band array by changing the states 16 p-i-n diode switches. This operates at 1.76/5.71 GHz with fractional bandwidth 8.6%/11.5% in L/ C-band operating states, respectively. measured realized gain radiation efficiency are 0.1/4.2 dBi 66.6%/80.7%, element spacing 5.71 0.36λ0, which enables beamsteering without grating lobes. shared-aperture...

A reconfigurable dual-polarized slot-ring antenna/ array, switching between Sand C-band with wide bandwidth in each operating state is presented. By simultaneously eight p-i-n diode switches, a 2 × antenna array can be reconfigured to an S-band unit cell, and vice versa. Fractal shapes are incorporated into the structure significantly enhance bandwidth. In S-/C-band state, this shows 69.1%/58.3% fractional measured maximum realized gain of 2.4/3.1 dBi. For 2×2 spacing elements less than 0.5...

Directly coupling antennas to filters can remove the transition loss between two and reduce size of radio frequency front ends. Circularly polarized (CP) patch with a single feed are very popular in many applications due their compact ease design. However, probe-fed CP antenna typically exhibits only 1%-2% useful fractional bandwidth by considering both impedance matching axialratio (AR) bandwidths. Thick substrates were used realize single-feed wider bandwidth. thick may cause issues, such...

In this article, tunable integrated filter/antennas are demonstrated with two coupling configurations that provide design control of the bandwidth performance over tuning range. The first is a single-layer third-order filter/antenna an increasing fractional (FBW). measured device has frequency range from 1.62 to 2.08 GHz, FBW 3.0% 4.8%, and gain -7.3 3.6 dBi. second double-layer vertically provides constant absolute This accounts for frequency-dependent behavior antenna radiation Q. 1.65...

Gallium is deemed to be a critical mineral given its irreplaceable use in consumer electronics and clean energy technologies. China has become significant of gallium while also playing leading role global production, accounting for more than 90% the world’s primary output recent years. However, quantification evolution China’s cycle limited until now. This study aims uncover dynamic flows stocks during period 2005–2020. The results reveal that: 1) From 2005 2020, demand increased 20-fold, as...

For hydrocarbon exploitation in tight glutenite, glutenite brittleness plays an important role fracturing efficiency, but the detailed effect is not entirely clear. In this study, considering rock heterogeneity, RFPA (Rock Failure Process Analysis) was applied to establish three-dimension computational model. An improved index post-peak properties uniaxial compression test proposed quantify brittleness. Results show that brittle can generate multiple failure surfaces under exterior loadings,...

The effect of PIN diode switches on the performance reconfigurable slot-ring antenna is studied and presented. An equivalent circuit used to model ON OFF states in structure. Two different antennas with ideal real are fabricated measured. Measured results show that have some loading effects antenna. Parametric analysis each element also simulated provided this paper. Numerical simulations using HFSS verified by measurements.

Metallic sodium, which has a suitable redox potential and high theoretical capacity, is regarded as an ideal anode material for rechargeable Na metal batteries. However, dendrite growth on sodium during cycling seriously restricted its practical applications. Herein, we employed low-cost facile brushing method to fabricate porous nano-SiO2 coating, can induce relatively uniform distribution of Na+ flux suppress the dendrites. The coating with porosity decrease stripping/plating overpotential...

An electrically tunable planar hairpin filter integrated with a microstrip patch antenna is proposed in this paper. The as resonator, contributing to second-order filter. integration performed eliminate 50-ohm transition losses and reduce the overall structure size. magnetically coupled resonator operates at center frequency of 3.03 GHz fractional bandwidth 2.38%. gain 5.41 dBi. Electrical tuning ability provided via four varactors response range from 2.77 3.19 GHz.

A novel design of frequency reconfigurable slot-ring antenna is proposed. The reconfigurability achieved by using PIN diode switches across each slot. Two operating states are defined based on different the (ON or OFF). Separate microstrip feed lines used to excite at lower (2.23GHz) and higher (6.81 GHz) bands two via holes etched away near center slot for biasing purposes. Numerical simulations HFSS show that bandwidth 10.2% 9.1% in bands, respectively, efficiency more than 91% both bands.

A circularly-polarized (CP) filter/antenna system is presented herein. The formed by a cavity resonator and single-fed corner-truncated patch antenna. works as both of the filter CP radiating element. By vertically integrating antenna with resonator, second-order filtering response obtained near-zero transition loss reduced size. operates at center frequency 10.08 GHz fractional bandwidth 11% an axial ratio 1.5%. gain 7.35 dBi. overall efficiency integrated approximately 96%.

A switchable S-/C-band antenna array is presented with dual polarization and modularity. 2 × S-band can be reconfigured into a 4 C-band within the same physical aperture. narrow ground strip inside slot-ring used to reduce mutual coupling between elements suppress null in radiation patterns array. In addition, vertical coaxial-tomicrostrip transition allows for feeding from behind plane, making it modular. Dual capability achieved each band. This shows 64.3% 66.7% fractional bandwidth 8.4...

The uneven spatial distribution of mineral resources necessitates the construction mature global governance system to ensure rational allocation resources. To this end, it is essential analyze structure provide a theoretical basis for construction. actor crucial element in driving process, and country serves as most central actor. Therefore, clarifying roles statuses different countries will be helpful system. In context advancing globalization, complex cooperative relationship has been...

An evanescent-mode cavity filter integrated with a slot antenna is presented herein. Evanescent-mode cavities are commonly used to design low-loss filters due their high quality (Q) factors and small size. The integration of the provides nearly-zero transition loss reduced filter/antenna designed at center frequency 8.56 GHz fractional bandwidth 2.86%. this then tuned from 8.18 8.80 by just changing resonant resonators. impedance matching, filtering shape, radiation pattern system preserved...

This paper presents a continuously-tunable single-polarized slot-ring antenna operating at S band. The frequency tunability is achieved by loading the with varactors. By properly designing feeding network and biasing circuits, able to cover 2-4 GHz. A prototype was fabricated measured. measured return loss better than 9 dB from 2.66 4.09 gain radiation pattern are very close simulation results. tunable can be extended for reconfigurable array both L band strategically placing switches...

In general, the radiation pattern of an antenna array can be predicted by factor and element. However, a reconfigurable slot-ring varies with ground plane size. To explore performance, effects size on is studied herein. Since geometries working at different frequency bands are similar, single slotring sizes 6.27 GHz studied. The number ripples in increases as increases, which due to edge diffraction. Both unit cell periodic boundary conditions 5×5 simulated HFSS. multiplying agrees very well...

According to open-phase fault condition occurred in power system, this paper proposes a new calculation method based on superposition principle. The network is equivalent the of disconnection state before faulting and an additional short-circuited state, after calculating two states respectively results acquired, formula electric quantity can be obtained. In paper, kinds during running are calculated: occurs faulty phase sound phase. formulation post-fault electrical quantities Numerical...

For microstrip patch phased arrays, larger fractional bandwidth (FBW) and wider scan angle are challenging to achieve at the same time. Phased arrays on thin substrates typically can large angles due reduction of mutual coupling caused by surface waves. However, limit achievable FBW array antenna. In this paper, an integrated filter/patch technology is proposed realize with capabilities enhanced bandwidth. addition, able provide filtering function which desirable for RF front ends. To prove...