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This paper aims to present the results of measurements and calculations illustrating mutual thermal coupling between power Schottky diodes made of silicon carbide situated in the common case.

The idea of measurements of mutual transient thermal impedances of the investigated device is described.

The results of measurements of mutual transient thermal impedances between the considered diodes are shown. The experimentally verified results of calculations of the internal temperature waveforms of the considered diodes obtained with mutual thermal coupling taken into account are presented and discussed. The influence of mutual thermal coupling and a self-heating phenomenon on the internal temperature of the considered diodes is pointed out.

The presented methods of measurements and calculations can be used for constructing the investigated diodes made of other semiconductor materials.

The presented results prove that mutual thermal coupling between diodes mounted in the common case must be taken into account to calculate correctly the waveforms of the device internal temperature.

In wireless communication system, use of multiple antennas for different requirements of system will increase the system complexity. However, reconfigurable antenna is maximizing the connectivity to cover different wireless services that operate different frequency range. Pattern reconfigurable antenna can improve security, avoid noise and save energy. Due to their compactness and better performance at different applications, reconfigurable antennas are very popular among the researchers. The purpose of this work, is to propose a novel design of S-shaped antenna with frequency and pattern diversity. The pattern and frequency reconfiguration are controlled via ON/OFF states of the PIN diode.

The geometrical structure of the proposed antenna dimension is 18 × 18 × 0.787 mm³ with εr = 2.2 dielectric constant. Three S-shaped patches are connected to a ring patch through PIN diodes. The approximate circumference of ring patch is 18.84 mm and length of patch is 5 mm, so approximate length of radiating patch is 14.42 mm and effective dielectric constant is 1.93. Conductor backed coplanar waveguide (CPW) is used for feeding. The proposed antenna is designed and simulated on CST microwave studio and fabricated using photolithography process. Measurements have been done in anechoic chamber.

Antenna shows the dual band operation at 2.1 and 3.4 GHz frequency. The first band remains constant at 2.1 GHz resonant frequency and 200–400 MHz impedance bandwidth. Second band is switched at seven different resonant frequencies as 3.14, 3.45, 3.46, 3.68, 3.69, 3.83 and 3.86 GHz with switching of the diodes. The −10 dB bandwidth is more than 1.4 GHz.

Pattern reconfigurability can be achieved using mechanical movement of antenna easily but it is not a reliable approach for planar antennas. Electronic switching method is used in proposed antenna. Antenna size is very small so fabrication is very crucial task. Measured results are deviated from simulation results due to fabrication error and effect of leads of diodes, connecting wires and battery.

The reconfiguration of the proposed antenna is controlled via ON/OFF states of the three PIN diodes. The lower band of 2.1 GHz is fixed, while second band is switched at five different resonant frequencies as 3.27, 3.41, 3.45, 3.55 and 3.88 GHz, with switching of the PIN diodes with all state of diodes and exhibit pattern reconfigurability at 2.1 GHz frequency. At second band center frequency is significantly changed with state of diodes and at 3.4 GHz pattern is also changed with state of diodes, hence antenna exhibits frequency and pattern reconfigurability.

A novel design of pattern and frequency reconfigurable antenna is proposed. Here, work is divided into two parts: first is frequency reconfiguration and second is radiation pattern reconfiguration. PIN diodes as switch are used to select the frequency band and reconfigure the radiation pattern. This proposed antenna design is novel dual band frequency and pattern reconfigurable antenna. It resonates at two distinct frequencies, i.e. 2.1 and 3.4 GHz, and has a pattern tilt from 0° to 355°. The conductor backed CPW feed technique is used for impedance matching.

Models of power semiconductor devices for use in circuit simulators need to take account of effects which can be neglected in low power device models; they then become very complex and difficult to parameterise. The power PIN diode model described in this paper demonstrates how the use of empirically derived look‐up tables can simplify the characterisation problem and how non quasi‐static effects can be incorporated

The purpose of this paper is to study and calculate the electrical characteristic of an equilateral triangular microstrip patch antenna that is proposed for dual frequency operation using the pin diode. The electrical characteristic of an equilateral triangular microstrip patch antenna is proposed for dual-frequency operation. Spur lines and ON/OFF condition of the pin diode are utilized to switch the resonant frequency of the patch. The presence of spur lines excites the surface current of the patch which is dependent on the resonant frequency of an equilateral triangular microstrip patch. Insertion of the diode in the spur lines gives a better result and compactness in patch design, which improves the miniaturization in size of patch.

Antenna Design Aspects: A basic structure of an equilateral triangular microstrip antenna (ETMA) having two spur lines and one pin diode positioned in between the spur line is considered in this paper. The design parameters are chosen on the basis of substrate materials having relative permittivity less than three. Specification of the antenna is given in Table I. Substrate material used is RT Duroid 5,880; relative permittivity of the substrate er is 2.2; thickness of dielectric substrate h is 1.5 mm; sides of equilateral triangular patch a are 10 mm, spur width s is 0.5 mm; and spur length b is 2.0 mm.

This paper gives an account of achieving polarization swiftness with coplanar waveguide (CPW) feed. The miniaturized size of the antenna is 35 × 30 mm2. Switchable microstrip equilateral triangular antenna has been demonstrated for dual-frequency operations. The resonant frequency of an ETMA can be adjusted by setting the diode in an ON and OFF state. The design improves the miniaturization in size with a discussion of radiation density. The excited patch surface current is limited to flow around just the mid of the patch in simple ETMA with a single slit cut. It is observed that for an ETMA, when the diode is in the ON state at 9.16 GHz, the excited patch surface current is highly distributed in the patch compared to when the diode is in the ON state at 11 GHz. Similarly, it is observed that the excited surface patch current is highly distributed when the diode is in the OFF state in both frequencies (9 and 11.96 GHz). The mode is changed by the use of a switch at time and it is suitable for wireless communication applications.

Spur lines and the ON/OFF condition of the pin diode are utilized to switch the resonant frequency of the patch. The presence of spur lines excites the surface current of the patch which is dependent on the resonant frequency of an equilateral triangular microstrip patch. Insertion of the diode in spur lines gives a better result and compactness in patch design, which improves the miniaturization in size of the patch.

The purpose of this paper is to propose a simple electrothermal model of GaN Schottky diodes, and its usefulness for circuit-level electrothermal simulation of laboratory-made devices is proved.

The compact electrothermal model of this device has the form of a subcircuit for simulation program with integrated circuit emphasis. This model takes into account influence of a change in ambient temperature in a wide range as well as influence of self-heating phenomena on dc characteristics of laboratory-made GaN Schottky diodes. The method of model parameters estimation is described.

It is shown that temperature influences fewer characteristics of GaN Schottky diodes than classical silicon diodes. The discussed model accurately describes properties of laboratory made GaN Schottky diodes. Additionally, the measured and computed characteristics of these diodes are shown and discussed.

The presented model together with the results of measurements and computations is dedicated only to laboratory-made GaN Schottky diodes.

The presented investigations show that characteristics of laboratory-made GaN Schottky diodes visibly change with temperature. These changes can be correctly estimated using the compact electrothermal model proposed in this paper. The correctness of this model is proved for four structures of such diodes characterised by different values of structure area and a different assembly process.

A “spin-diode” is the spintronics equivalent of an electrical diode: applying an external magnetic field greater than the limit of spin-diode BT flips the spin-diode between an isolating state and a conducting state [1]. While conventional electrical diodes are two-terminal devices with electrical current between the two terminals modulated by an electrical field, these two-terminal magneto resistive devices can generally be referred to as “spin-diodes” in which a magnetic field modulates the electrical current between the two terminals.

Current modulation and rectification are an important subject of electronics as well as spintronics spin diode is two-terminal magnetoresistive devices in which change in resistance in response to an applied magnetic field; this magnetoresistance occurs due to a variety of phenomena and with varying magnitudes and directions.

In this paper, an efficient rectifying spin diode is introduced. The resulting spin diode is formed from graphene gallium and indium quantum dots and antimony-doped molybdenum disulfide. Converting an alternating bias voltage to direct current is the main achievement of this model device with an additional profit of rectified spin-current. The non-equilibrium density functional theory with a Monte Carlo sampling method is used to evaluate the flow of electrons and rectification ratio of the system.

The results indicate that spin diode displaying both spin-current and charge-current rectification should be possible and may find practical application in nanoscale devices that combine logic and memory functions.

The purpose of this paper is to deal with material and technological aspects of SiC diodes assembly in ceramic packages. The usefulness of combinations of different materials and assembly techniques for the creation of inner connection system in the ceramic package, as well as the formation of outer connections able to work at temperatures up to 350°C, were evaluated.

The ceramic package consists of direct bonded copper (DBC) substrate with Cu pads electroplated by Ni or Ni/Au layers on which a SiC diode was assembled by sintering process using Ag microparticles. For the connections inside the ceramic package, the authors used Al/Ni and Au-Au material system based on aluminium or gold wire bonding. The authors sealed the ceramic package with glass encapsulation and achieved a full encapsulation. Outer connections were manufactured using Cu ribbon plated with Ag layer and sintered to DBC by Ag micro particle. The authors investigated the long-term stability of electrical parameters of SiC diodes assembled in ceramic package at temperature 350°C.

The authors have shown that Schottky and PiN SiC diodes assembled with different technologies and materials in ceramic package keep their I-V characteristics unchanged during ageing at 350°C for 400 h.

The SiC diodes assembled into ceramic package with Al/Ni or Au-Au inner electrical connection systems and outer connections system based on Ag microparticles sintering process of Cu/Ag ribbon to DBC substrate can work reliably in temperature range up to 350°C.

The purpose of this paper is to present an electrothermal model of the module containing power light emitting diodes (LEDs) situated on a common base.

The electrothermal model of this device, which takes into account both self-heating and mutual thermal coupling between the diodes situated in this module, is described.

The correctness of the presented model is verified experimentally, and a good agreement of the calculated and measured optical and thermal characteristics of the considered module is obtained.

The presented model can be used for different structures of the LED module, but electrical inertia in the diodes is omitted.

The presented model was used to calculate electrical, thermal and optical waveforms of the module OSPR3XW1 containing three power LED situated on the common base.

The presented model takes into account thermal inertia in the considered LED module and its cooling systems with mutual thermal coupling between all the diodes situated in the same module.

This paper aims to present the results of investigations that show the influence of soldering process parameters on the optical and thermal parameters of power LEDs.

The power LEDs were soldered onto metal core printed circuit board (MCPCB) substrates in different soldering ovens: batch and tunnel types, characterized by different thermal profiles. Three types of solder pastes based on Sn99Ag0.3Cu0.7 with the addition of TiO₂ were used. The thermal and optical parameters of the diodes were measured using classical indirect electrical methods. The results of measurements obtained were compared and discussed.

It was shown that the type of oven and soldering thermal profile considerably influence the effectiveness of the removal of heat generated in the LEDs tested. This influence is characterized by thermal resistance changes. The differences between the values of this parameter can exceed 20%. This value also depends on the composition of the soldering paste. The differences between the diodes tested can exceed 15%. It was also shown that the luminous flux emitted by the diode depends on the soldering process used.

The results obtained could be useful for process design engineers for assembling power LEDs for MCPCBs and for designers of solid-state light sources.

This paper presents the results of investigations into the influence of the soldering profiles and soldering pastes used on the effectiveness of the removal of heat generated in power LEDs. It shows and discusses how the factors mentioned above influence the thermal resistance of the LEDs and optical parameters that characterize the light emitted.

The purpose of this paper is to present a new method of measuring thermal resistance of power light-emitting diodes (LEDs). Properties of power LEDs strongly depend on their internal temperature. The value of this temperature depends on the cooling conditions characterized by thermal resistance.

The new method of measuring the value of this parameter belongs to the group of electric methods. In this method, the problem of estimating the value of electrical power converted into light is solved. By comparing the values of the case temperature obtained for the LED operating in the forward mode and the reverse-breakdown mode, the thermal power is estimated. On the basis of the measured value of the thermally sensitive parameter (the LED forward voltage) and the estimated value of the thermal power, thermal resistance is calculated.

The elaborated method was used to measure thermal resistance of the selected types of power LEDs operating at different cooling conditions. The correctness of the elaborated measurement method was proved by comparing the results of measurements obtained with the use of the new method and the infrared method.

On the basis of the obtained results of measurements and the catalog data of the tested diodes, the dependence of the measurement error of thermal resistance of the LED on its luminous efficiency is discussed.

The new measurement method is easy to use and more accurate than the classical method of thermal resistance measurement of the diode.