On Solving TM_(0n) Modal Excitation in a Ka-Band Overmoded Circular Waveguide by the Conservation of Complex Power Technique

To measure the radiation properties of relativistic diffraction generator （RDG） in Ka-band, a TMon modal excitation model is established, which consists of an overmoded circular waveguide and a coaxial line feeding probe. Using the transverse E-field mode matching and the conservation of complex power technique （CCPT）, we deduce the scattering matrix at coaxial line to coaxial line and coaxial line to circular waveguide junctions. Then using the overall cascaded junction scattering matrix, the numerical results for the reflection coefficient of the coaxial line and the power distribution of TMon multi-modal are presented. The numerical results are in agreement with HFSS simulation results and experimental results. The analysis shows that by choosing the appropriate position of coaxial line probe, the power proportion of the device operating mode excited in circular waveguide could be the largest.

One-dimensional dynamic equations of a piezoelectric semiconductor beam with a rectangular cross section and their application in static and dynamic characteristic analysis

Within the framework of continuum mechanics, the double power series ex- pansion technique is proposed, and a series of reduced one-dimensional （1D） equations for a piezoelectric semiconductor beam are obtained. These derived equations are universal, in which extension, flexure, and shear deformations are all included, and can be degen- erated to a number of special cases, e.g., extensional motion, coupled extensional and flexural motion with shear deformations, and elementary flexural motion without shear deformations. As a typical application, the extensional motion of a ZnO beam is analyzed sequentially. It is revealed that semi-conduction has a great effect on the performance of the piezoelectric semiconductor beam, including static deformations and dynamic be- haviors. A larger initial carrier density will evidently lead to a lower resonant frequency and a smaller displacement response, which is a little similar to the dissipative effect. Both the derived approximate equations and the corresponding qualitative analysis are general and widely applicable, which can clearly interpret the inner physical mechanism of the semiconductor in the piezoelectrics and provide theoretical guidance for further experimental design.

Interleaved high-gain boost converter powered by solar energy using hybrid-based MPP tracking technique

This paper presents a solar-powered interleaved high-gain boost converter(IHGBC)that increases voltage gain with fewer ripples in the output voltage in comparison to existing DC-DC converters.The goal of this research is to develop a hybrid-based maximum power point tracking(MPPT)approach with the combination of a flower pollination(FP)algorithm assisted with a perturb&observe(P&O)MPPT approach for solar photovoltaic(SPV)systems integrated with IHGBC.To ensure effective usage of both FP and P&O algorithms,this study incorporates and validates the hybrid-based MPPT approach.The proposed solar-powered IHGBC with a hybrid-based MPPT algorithm has been computationally modelled and simulated using MATLAB®and Simulink®for both uniform and non-uniform irradiation and analysed for voltage gain,ripples in the output waveforms and convergence time.The proposed hybrid-based MPPT is based on a number of flowers that forecast the initial global peak,assisted by P&O in the last stage for faster convergence to attain the maximum power point(MPP).As a result,the hybrid-based MPPT approach alleviates the computational issues encountered in P&O and FP-based MPP approaches.The proposed hybrid MPPT is compared with conventional MPPT for SPV and the results show that the solar-powered IHGBC using a hybrid-based MPPT technique has negligible oscillations of 0.14%with a high-voltage gain of 7.992 and a fast convergence rate of 0.05 seconds compared to individual P&O-based MPPT and FP-based MPPT techniques.The simulation results of the proposed MPPT with IHGBC outperform the conventional MPPT with high-gain converters.

Performance comparison of power fading mitigation techniques in multiband OFDM-UWB signals transmission along LR-PONs

The single sideband （SSB） modulation is assessed as a means to mitigate the dispersion-induced power fading on the distribution of ortogonal frequency division multiplexing （OFDM） ultra wideband （UWB） radio signals along long-reach passive optical networks （LR-PONs）. Particularly, two different SSB ar- chitectures, namely, Sieben＇s architecture and four phase modulator （FPM） architecture are optimized to provide maximum sideband suppression. The minimum optical signal-to-noise ratio （OSNR） required to simultaneously distribute all the 14 OFDM-UWB sub-bands along the LR-PON distances ranging between 80 and 100 km is also evaluated through numerical simulation. FPM architecture is preferable over Sieben＇s architecture because the latter SSB architecture generates carriers-carriers beat term at the photodetector output with high power, thereby causing significant degradation in the OFDM-UWB sub-bands with lower central frequencies. The simultaneous distribution of the 14 SSB OFDM-UWB sub-bands in the LR-PON using the FPM architecture shows a minimum OSNR penalty of 3 dB compared with the centralized dis- persion compensation technique.

A 320 mV,6 kb subthreshold 10T SRAM employing voltage lowering techniques

This paper presents a 6 kb SRAM that uses a novel 10T cell to achieve a minimum operating voltage of 320 mV in a 130 nm CMOS process. A number of low power circuit techniques are included to enable the proposed SRAM to operate in the subthreshold region. The reverse short channel effect and the reverse narrow channel effect are utilized to improve the performance of the SRAM. A novel subthreshold pulse generation circuit produces an ideal pulse to make read operation stable. A floating write bit-line effectively reduces the standby leakage consumption. Finally, a short read bit-line makes the read operation fast and energy-saving. Measurements indicate that these techniques are effective, the SRAM can operate at 800 kHz and consume 1.94/zW at its lowest voltage （320 mV）.

Low power DCVSL circuits employing AC power supply

In view of changing the type of energy conversion in CMOS circuits, this paper investigates low power CMOS circuit design, which adopts a gradually changing power clock. First, we discuss the algebraic expressions and the corresponding properties of clocked power signals. Then the design procedure is summed up for converting complementary CMOS logic gates employing DC power to the power-clocked CMOS gates employing AC power. On this basis, the design of differential cas-code voltage switch logic (DCVSL) circuits employing AC power clocks is proposed. The PSPICE simulations using a sinusoidal power-clock demonstrate that the designed power-clocked DCVSL circuit has a correct logic function and low power characteristics. Finally, an interface circuit to convert clocked signals into the standard logic levels of a CMOS circuit is proposed, and its validity is verified by computer simulations.