Development and Research of Three-Channel Power Divider for the Decimeter Range

The implementation of industrial revolution 4.0 in manufacturing industries is necessary to adapt to the rapid changes of technologies. The milling process is one of the common manufacturing processes applied in the industries to produce engineering products. The vibration that occurs in the milling process can disturb the continuity of the process. The wired vibration monitoring system implemented in the manufacturing process needs to be replaced with the wireless monitoring system. Hence wireless vibration monitoring system is developed to solve the problem with wired monitoring systems where tucked cable and high cost are the main challenges of the wired monitoring system. The wireless monitoring system setup is built using three components: sensor node, monitoring node, and base station. Milling experiments with various depths of cut, feed rate, and spindle speed were conducted to examine the performance of the wireless monitoring system. The results indicate the wireless system shows similar data recorded by the wired system. The wireless vibration monitoring system can identify the effect of milling parameters such as depth of cut, feed rate, and spindle speed on the vibrations level. The effect of cut depth is more significant than spindle speed and feed rate in the defined parameters.

A compact microstrip multifunctional reconfigurable filtering power divider (FPD) is proposed based on varactor‐loaded three‐parallel‐coupled line section (TLCS) in this letter. Continuously tunable third‐order filtering power division response with two transmission zeros (TZs) including centre frequency (CF), bandwidth (BW) and power division ration (PDR) is successfully attained by varying the external and internal coupling through loading varactors into a three‐parallel‐coupled line topology. For validation, a prototype is implemented. The results indicate that the CF can be tuned from 0.46 to 0.8 GHz, a tunable 3‐dB BW of 80 to 190 MHz is exhibited with better than 17‐dB return loss and higher than 15‐dB in‐band isolation. In addition to the CF and BW tunability, the power division ratio (PDR) for the presented FPD can also be adjusted from 1:1 to 1:5. Additionally, a compact size is realized with only 0.12λg × 0.16λg.

Nowadays, 5G antennas are one of the big topics in the development of communication technology. The power dividers have a large role in microwave circuits and it is very important in antenna array system. In this paper, a power divider with multiple outputs for a large scale 5G antenna feeding system MIMO (Massive MIMO) that can operate at Sub-6 GHz frequency will be proposed. The Wilkinson power divider with 1 input and 8 outputs was designed compactly and fabricated by using a dielectric substrate of FR-4. The design concept, simulation and optimization development was carried out by using a software of CST Microwave Studio. The reflection coefficient and transmission coefficient at the operating frequency of 3.5GHz (3.3GHz–4.2GHz) were observed by referred to the specified design features and optimization has been made. The patch antennas has been applied to a power divider for a simulation to analyze its performance. The power divider with 1 input and 8 outputs has a reflection coefficient less than −10dB and a transmission coefficient in between of −10.5dB until −13.5dB (3.3GHz–4.2GHz) which are meet with the requirement of design features.

This paper proposes a design of wireless monitoring system of tower body running state such as tilt angle, temperature, humidity, wind speed, etc. This design adopts the structural health monitoring (SHM) techniques to monitor the state of tower, and can be applied to both the power transmission tower and the communication tower. Although the SHM has been widely applied to civil engineering and building structures subjected to various loadings, there are few applications in the running state monitoring for the power transmission and communication towers. In this study, micro-electro-mechanical system (MEMS)-based acceleration sensor is used, in which a method is employed for calculating the tilt based on the difference between the acceleration due to combination of gravity and other stresses and the acceleration due to gravity alone. The wireless system uses wireless sensor nodes to transmit the tower running state data to the monitoring server. The wireless sensor node system consists of a short-distance wireless transmission network (ZigBee 2.4GHz) and a remote telecommunication network (Global System for Mobile Communication - GSM). By so doing, the important problem about the communication distance limitation is resolved. The performance of the monitoring system is evaluated through several experiments. The experimental results indicate the wireless monitoring system can accurately monitor the tower body running state in real time.

In this paper, 1 to 4 power divider is designed for 60GHz in the millimeter wave frequency range for upcoming new technologies in wireless communications. To design this power divider Rogers RT/Duriod 5880 Substrate material is used with a dielectric constant as 2.2 and electric loss tangent as 0.0009. This power divider analyzed the characteristic like reflection coefficient, voltage standing wave ratio and electric fields. This power divider gives max reflection coefficient of −39.95 dB at 60GHz, voltage standing wave ratio of 1.02 and transmission coefficients are −6.67dB and −5.7 dB at 60GHz. This power divider gives 2.42 GHz as bandwidth. Dimensions of the 1 to 4 power divider are 6∗16∗0.508mm3. Due to its dimensions and bandwidth this power divider is more suitable for millimeter wave applications like RADAR and 5G applications at 60 GHz for today's society need.

Slope stability is one of the primary problems faced by opencast mines. The conventional geotechnical sensors are monitored by technicians in the field and the available wireless monitoring systems like slope stability radar (SSR), light detection and ranging (LiDAR) are more expensive. Critical observations on recent low-cost wireless slope monitoring systems were presented. By deploying the wireless data transmission system using advanced antennas at respective slope instruments in underground or opencast mines, we can collect data without any physical connections. Wireless sensor networks (WSNs) are well suited to monitor the movement, and it consists of sensor nodes which measure physical quantities and transmit the pre-processed measurement results to a base station. Developments in information and communications technology (ICT) support the collection, connection and analysis of data through sensing and monitoring of slopes in mines. This paper gives the detailed review on available low-cost wireless slope monitoring systems for opencast mines.

Slope stability is one of the primary problems faced by opencast mines. The conventional geotechnical sensors are monitored by technicians in the field and the available wireless monitoring systems like slope stability radar (SSR), light detection and ranging (LiDAR) are more expensive. Critical observations on recent low-cost wireless slope monitoring systems were presented. By deploying the wireless data transmission system using advanced antennas at respective slope instruments in underground or opencast mines, we can collect data without any physical connections. Wireless sensor networks (WSNs) are well suited to monitor the movement, and it consists of sensor nodes which measure physical quantities and transmit the pre-processed measurement results to a base station. Developments in information and communications technology (ICT) support the collection, connection and analysis of data through sensing and monitoring of slopes in mines. This paper gives the detailed review on available low-cost wireless slope monitoring systems for opencast mines.

A method is presented for broadbanding an n‐way power divider in which an absorbing resistor is used in one section. In the conventional Wilkinson power divider, it is known that the waves, equally reflected at the terminations, are absorbed by a resistor at the center frequency if a quarter‐wave line is connected to one of the output ports. To construct a 2n‐way power divider from a combination of these two‐way power dividers, 2n sections of lines are needed. In this paper, we constructed a network, which absorbs reflected waves, by connecting a 1/4‐wavelength section to an n‐way one‐section power divider if the characteristic impedance of the line and the absorbing resistor are optimized by numerical calculation. The circuit shown in the text has a broadband VSWR characteristic if attenuation of the transfer at the center frequency is permitted. The transmission characteristics then become flat, and the isolation characteristics are also improved.

Expressions for power reflection (R), transmission (T) and absorption (A) coefficients for p‐polarized wave for a warm, collisional, magnetized and moving plasma slab (with sharp boundaries and thickness d0) are investigated. The effects of plasma slab velocity (β=v/c), electron density (ωp/ω)2 and plasma temperature (KBT) on reflection (R), transmission (T) and absorption (A) coefficients are discussed numerically. It is observed that for the value β=−0.6, reflection coefficient (R) becomes more than unity, whereas absorption coefficient (A) becomes quite negligible while transmission coefficient (T) shows oscillatory behaviour. The variation with plasma frequency (ωp/ω)2 shows that at lower plasma frequency (ωp/ω)2=0.2 transmission (T) and absorption (A) coefficients are minimum while reflection coefficient (R) is maximum.

In order to monitor in real time the growth environment of a mountain citrus orchard and its variation with spatio-temporal and weather status, the optimal design and evaluation of a wireless monitoring system in a mountain citrus orchard was introduced in this paper. The wireless monitoring system is comprised of end nodes used for obtaining citrus growth environment information including air temperature, air humidity, soil moisture and light; router nodes used to relay citrus growth environment information; and a network coordinator, which performs functions such as managing the nodes, collecting and analyzing the data received from the end nodes, and connecting as a gateway for remote data access. CC2530 is adopted as the core processor of the monitoring system; it has the capability of wireless communication and central processing. The optimal design was introduced in this system including information frame structure suitable for a mountain orchard environment, bidirectional instruction control function, topology discovery, routing monitoring mechanism and node information diversification collection mechanism, so as to effectively enhance the robustness and controllability of monitoring the citrus orchard environment. In this paper, the citrus orchard in the subtropical garden of SCAU (South China Agriculture University) was selected for the test. The orchard hill has sloping terrain; citrus trees are planted by terraced distribution. The average slope is 20 degrees, the citrus trees have a height of 2.8m, their shrub diameters are 3m, and the average spacing of citrus plants is 2.8m. The citrus orchard wireless channel was measured in citrus orchard, and the wireless channel model was established through blocking factor and rain attenuation factor, it was used to guide the evaluation of the wireless monitoring network. Experimental results of RSSI (Receiver Signal Strength Index) and communication quality under different distances and climates show that reliable collection and transmission were available in the mountain citrus orchard when the wireless system was deployed with an antenna height of 1.5m and a maximum single-hop communications distance of 30m. Continuous 744h online test results show that the optimized wireless monitoring system improved the transmission success rate; it has a success rate of at least 99.12% for data transmission within the 30m distance. The system ran well, worked stably, and was suitable for the remote, real-time monitoring of the citrus growth environment in a mountainous orchard.

The submerged U-shape breakwater interaction with the solitary wave is simulated by the Boussinesq equations using the finite-difference scheme. The wave reflection, transmission, and dissipation (RTD) coefficients are used to investigate the U-shape breakwater's performance for different crest width, Lc1, and indent breakwater height, du. The results show that the submerged breakwater performance for a set of U-shape breakwater with the same cross-section area is related to the length of submerged breakwater crest, Lc1, and the distance between the crests, Lc2 (or the height of du). The breakwater has the maximum performance when the crest length is larger, and at the same time, the distance between them increases. Changing the Lc1 and du of the U-shape breakwaters result in a significant change in the RTD coefficients. Comparison of the U-shape breakwater, having the best performance, with the averaged RTD values shows that the transmission coefficients, K_t, has a better performance of up to 4% in comparison to other breakwaters. Also, the reflection coefficients K_R and the diffusion coefficients, K_d shows a better performance of about 30% and 55% on average, respectively. However, the model governing equations are non-dissipative. The non-energy conserving of the transmission and reflection coefficients due to wave and breakwater interaction results in dissipation type contribution. The U-shape breakwater with the best performance is compared with the rectangular breakwater with the same cross-section area to investigate the economic advantages of the U-shape breakwater. The transmission coefficients, K_t, of the U-shape breakwater shows a better performance of 5% higher than the rectangular one. The reflection coefficient, K_R, is 60% lower for U-shape in comparison to rectangular one; however, the diffusion coefficients, K_d, of U-shape breakwater is 35% higher than the rectangular breakwater. Therefore, we could say that the U-shape breakwater has a better performance than the rectangular one.

In this paper, a novel design of compact substrate integrated waveguide (SIW) dual-band power divider is proposed. The dual-band operation of the power divider is obtained by exploiting the loading of slots on the ground plane. The electric-dipole nature of these slots allows the power divider to exhibit a passband below the cutoff frequency of the SIW. An in-depth description of the proposed power divider, supported by detailed parametric analysis over the operating frequency bands is reported. Design examples are illustrated to achieve different operating frequency bands. To validate the design studies, a prototype of the dual-band power divider operating at 4.7 GHz and 11.7 GHz is designed, fabricated and tested. The measurement results are found to be in good agreement with the simulation results.

An interlayer junction for three-row EBG waveguides integrated with a two-channel power divider was studied. It is shown that without additional matching such transitions are relatively narrow-band in terms of reflection coefficient in the frequency band 8…12 GHz. To expand the matching band, a modified transition with additional matching rods in both waveguide channels on the power divider layer is proposed. Using numerical analysis, it was found that due to this in the frequency band under study, it is possible to obtain a symmetrical matching curve with two well separated minima and with a matching level no worse than –20 dB in the central part of the range. It is shown that in the structure with matching rods, the operating frequency band by reflection coefficient is significantly expanded in comparison with the original structure.

The wireless communication system is one of the most important facilities of fuel cell hybrid power tram (FCHPT), which provides a strong guarantee for efficient and safe operation. As an indispensable part of the RF front-end of the transmitter and receiver, the miniaturization and high-performance trends of filtering power dividers are becoming evident. Based on the principle of filter power divider, a capacitor loaded power divider filter is designed and fabricated in this paper. The center frequency of the designed power divider filter is 30 GHz, the return loss S11 is less than −10 dB in the range from 29.2 to 31.6 GHz, and the insertion losses S21 and S31 are less than 5.3 dB. The frequency shift of 1.8 GHz can be achieved by changing the dielectric constant of the liquid crystal with an applied bias voltage, which can be used in millimeter wave communication system.

As the quality of building energy management systems has been taken seriously by more and more people, finding an efficient way to gather and release information for the system is of great importance. Compared with the wired monitoring system, the wireless system has many advantages, such as flexibility and economy, when applied in buildings. However, most wireless monitoring systems are composed of nodes with different functions and the communication protocols are not standard or transparent, which, therefore, is difficult to track the malfunctions and complicated for unprofessional users. In order to promote standardization of wireless networks applied in buildings and making it easier to manage and extend, the current article has developed a self-organized wireless network based on the Wi-Fi Direct technology to monitor the environment for large-scale buildings. In this network, all the nodes are identical in function and the communication is based on the Transmission Control Protocol/Internet Protocol. A distribute data processing mechanism to rectify the outliers is utilized in the network. The performance of the proposed network has been testified through both simulations and experiments. The results have shown that the proposed monitoring system has advantages, such as dynamic in structure, easy to extend, transparent in communication, and distributed in data processing.