Two bandwidth-enhanced broadband dual-polarized antennas (BEBDPAs) are proposed for 2G/3G/4G wireless communication systems and international mobile telecommunication services. The first BEBDPA is composed of two perpendicularly crossed dipoles. Its bandwidth enhanced by introducing a parasitic loop below the dipoles disk with four strips above. achieves an impedance 64% reflection coefficients <;-15 dB (1.4-2.75 GHz) isolation 30 dB. second based on pair dual-dipole elements above...

A new approach is proposed to develop aperture-shared dual-band antennas using partially reflecting surfaces (PRSs). fully antenna consisting of a low-band (LBA) and high-band (HBA) right below the LBA first investigated. The aperture sharing has little influence on but causes severe shielding effect HBA. To alleviate effect, low-pass PRS inserted between HBA, forming an air-filled quasi-Fabry&#x2013;Perot cavity, which can make compensation for radiation from HBA with LBA. second introduced...

A front-to-back pattern-reconfigurable antenna based on two dipoles is investigated. The theory for a pattern reconfiguration analyzed. ratio (F/B) improved by using folded dipoles. realized switching PIN diodes with broadband baluns. Two parasitic elements are introduced the improvement of impedance bandwidth and bandwidth. shorter dipole added to each further enhancing Experimental results show that achieves 31.4% return loss >10 dB pattern-bandwidth 20.8% F/B > 10 11.5% 15 dB.

A new broadband flush-mountable dual-polarized antenna with very high isolation is proposed. The made up of a pair crossed slots that are fed by two orthogonal microstrip feedlines. metallic cavity introduced to back the slot for unidirectional radiation pattern. By setting feedlines on substrate layers separated metal ground which etched, achieves 40 dB. has broad bandwidth (BW) about 47%, due wide and impedance matching It shown can be easily flush mounted surface without affecting BW...

With an increase in extreme and complex work conditions the fields of aircraft industry high-speed train, single surface strengthening or machining is not satisfactory with repeated requests spherical plain bearings, which results serious wear. Therefore, this paper, a compound method ultrasonic rolling process texture was proposed on basis investigating wear mechanism to meet tribological property requirements bearings. The theoretical experimental show that low micro-hardness shear...

An eight-element broadband wide-beam circularly polarized (CP) antenna array is developed for mobile wireless communications. The CP element consists of two rectangular loops with gaps circular polarization and parasitic elements bandwidth enhancement. A wide beamwidth achieved in the horizontal plane because have a narrow cross section plane. also has higher isolation between than linear (LP) same space, which due to mismatch caused by currents elements. achieves 40% (1.7-2.55 GHz) return...

Abstract A simple method is proposed for the realisation of compact dual‐polarised antennas. The aperture area a dipole antenna can be reduced by half surrounding with square loop. Based on method, broadband developed. consists two ±45°‐polarised dipoles surrounded loop and fed orthogonal baluns. resonance at sfrequency ( f Lr = 0.7 GHz) created loop, leading to size about λ /4 × /4, where wavelength in free space . Another higher frequency Hr 1.5 generated etching open slots dipoles....

The extreme and complex working conditions require aviation spherical plain bearings not only to have high machining accuracy low surface roughness, but also possess microhardness lubricant retaining capability. This paper presents a vibration assisted strengthening approach achieving the synergistic effects of property-improving appearance-improving. research attempts answer how technique can improve tribological properties bearing components particularly in light proposing flat-headed...

A novel artificial magnetic conductor (AMC) surface based on spiral strips is proposed, which consists of 9 × AMC cells. Each cell includes a strip to increase its inductance, thus featuring wide bandwidth 42% for ±90° reflection phase. The applied three planar dipole antennas lowering the antenna heights, including linearly polarised (LP) antenna, dual‐polarised (DP) and circularly (CP) antenna. It shown by simulation experiment that LP achieves an impedance 40% (0.68–1.02 GHz) | S 11 &lt;...

By using ANASYS finite element analysis software to analyze the first three order resonance frequencies and strain values of porous free structure acoustic sensing chips, optimization indicates: frequency varies lower relatively, but stress improves relatively higher, we utilize beam membrane structure, featured size thickness is 50 um. We MEMS technology fabricate vibration sensor chips on single crystalline silicon, use second mode test unit measure signal, condition 5v power supply,...

Firstly this paper introduces gray relation analysis, and then it draws various reasons of electromagnetic flowmeter malfunction in combination with data provided by one company. And the calculates probabilities adopting classical statistics, equalizes these failure rate to get sequence difference, obtains grey incidence coefficient correlation degree. Then sorts degrees confirm influence degree modes. Finally, bleaching information required is obtained.

According to the Biot-Savart's Law, principle of detecting system which measures grade iron concentrate is analysed in this paper. It carries out an analysis influence inductance sensor coil structure parameters on performance sensor. The finite element model air core established and simulation done sensors by using orthogonal method. different structural parameters, relation magnetic permeability can be established. Moreover, effect coil’s parameter linearity sensitivity also determined....

Abstract Aviation spherical plain bearing often undergoes serious wear due to its extreme and complex working condition. This paper presents a solution of vibration assisted strengthening surface micro-texture for the aviation achieve synergistic effects property-improving appearance-improving. On basis analysis mechanism systematically, it attempts scientifically understand how micro texture can decrease by proposing distribution function asperity height contact theory. The are prepared...