Compact Half Research Articles

Compact all-optical half adder based on topology optimization

We proposed an inverse-designed compact half adder on a silicon-on-insulator platform with a footprint of 2µm×2µm. The optical power of SUM and CARRY is controlled by different input combinations, according to the truth table of a half adder. Topology optimization is applied to cope with multiple objective functions in such a combinational logic circuit. The transmittance at 1550 nm for CARRY with 11 input is 170.2%, with extinction ratios (ERs) of 27.1 and 5.8 dB for SUM and CARRY, respectively. The SUM and CARRY outputs have ERs over 22.0 dB and 5.7 dB from 1515 nm to 1600 nm. Phase condition and morphology analysis show that the device has high tolerance on phase fluctuation and fabrication. The proposed device with compact footprint, low insertion loss, and large bandwidth presents a novel, to the best of our knowledge, approach to achieve all-optical combinational logic circuits with inverse design.

Compact half H‐shaped dielectric resonator antenna for wideband applications

AbstractIn this study, the authors present the design of a half H‐shaped dielectric resonator antenna (DRA) for compact size and wide bandwidth. The trapezoidal patch feed is used to excite the DRA, which results in TE113Y and TE115Y resonant modes of the rectangular DRA (RDRA). It is found that the broad‐side higher‐order TE113Y with the TE115Ymode is used in the proposed design to make it wideband. The effective dielectric constant of the proposed DRA is reduced by the slots and then the structure is made half to make it compact. Finally, for further improvement in bandwidth, the size of the ground plane is reduced, which increases the parallel capacitive reactance and decreases the Q‐factor. The proposed structure achieves measured impedance bandwidth S11 ≤ −10 dB of 75% (4.30–9.50 GHz) with a maximum gain of 7.20 dB. The proposed DRA is applicable for WLAN (5.15–5.72 GHz) and orthogonal frequency‐division multiplexing 802.11a (5.72–5.85 GHz).

A compact half butterfly chipless RFID tag based on image theory with DER analysis

In this paper, a compact RFID chipless structure is designed, simulated, and fabricated. Image theory has been used to reduce the structure of the RFID tag so that it halves the tag and creates a PEC wall having the same resonant frequencies. In other words, each symmetric structure by this method is half the size with features similar to the original structure. The proposed structure has a ratio of area to lambda equal to 0.05 in which there are nine resonances in a frequency band of 4.3–8.5 GHz with dimensions of 14 × 7 mm2 in a bit density of 9.18 bit/cm2 and fabricated on Rog4003 substrate. The bit density for the full structure was equal to 4.59 bit/cm2. The original and proposed structures have similar resonances that indicate the accuracy of the proposed method. Also, this method can be used to create a label with a higher number of bits. The simulation results using HFSS software were in good agreement with the measurement results. Furthermore, the calculated detection error rate of the proposed structure was lower than the original one.

Compact half step approximation in exponential form for the system of 2D second-order quasi-linear elliptic partial differential equations

ABSTRACTThis paper deals with devising a novel exponential scheme, implicit in nature, using half step discretization of order four for computing the numerical solution of quasi-linear elliptic partial differential equations of the type , . Nine mesh points in a single compact cell are being used in this method. An elaborate convergence analysis of the proposed method has been worked out. The technique for a scalar equation is eventually extended to solve the systems of quasi-linear elliptic equations. The technique is then applied to noteworthy problems and computational outcomes corroborate the theoretical rate of convergence. Linear and non-linear singular problems are tackled separately ensuring the usage of nine spatial grid points of a single computing cell.

Double Layers of Truncated Semi Rectangular Monopole Design with Trimmed Half Ground Plane

In this research, a new extreme compact half rectangular monopole antenna with modified ground plane is proposed. The antenna is composed of a semi rectangular radiator with modified partial ground plane. The ground plane contains I shapes slots providing ultra-wide operating frequency from 2.6 till 14 GHz based on − 10 dB standard. In addition, the proposed monopole is characterized by its extensively reduced structure. The patch is printed on a substrate material of Rogers Duriod RT5880, which has relative permittivity of $$\epsilon r = 2.2,$$ with a total size of 10 × 14 × 0.9 mm3. The antenna has been studied, and optimized with respect to impedance matching, bandwidth, size, radiation characteristics, and fabrication cost. Both simulation results and experimental measurement are shown with good agreement. The proposed design results show that the monopole is suitable for ultra-wide band systems.

A compact half and quarter-wave plate based on bi-layer anisotropic metasurface

In this letter, an ultrathin bi-layer metasurface, which exhibits half- and quarter-wave plate operation at different resonance frequencies in the microwave regime, is realized and experimentally demonstrated. The proposed metasurface not only transforms linear and circular polarizations to their corresponding cross polarizations but also achieves linear-to-circular and circular-to-linear polarization conversion in different frequency regimes. Moreover, the quarter-wave plate operation of the metasurface is quite robust to the variations in the incidence angle both for transverse-electric and transverse-magnetic polarizations. The physical mechanism behind half- and quarter-wave plate operation is elucidated through surface current distribution. Analytical results for the refractive index further elaborate on the operation of the metasurface.

A novel circularly polarized half mode circular substrate integrated waveguide antenna using meandered strip feeding technique

A technique to design a compact half mode substrate integrated circular cavity (HMSICC) cavity backed antenna is presented in this letter. The proposed antenna achieves left-handed circularly polarized(LHCP) using a crossed slot, The feeding meandered stripline on the middle layer are able to achieve better impedance match and axial ratio bandwidth. Measured results show that the prototype achieves a bandwidth of 10.5% for −10dB return loss, axial ratio(AR) bandwidth is about 3% with maximum gain of 6.5dBi. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:668–673, 2016.

Broadband Gap-coupled Variations of Equilateral Triangular Microstrip Antennas

Various broadband multi-resonator gap-coupled configurations of equilateral triangular microstrip antenna and its compact variation, half equilateral triangular microstrip antenna, are proposed. The broadband proximity fed equilateral triangular microstrip antenna yields bandwidth of more than 650 MHz (~44%), whereas equivalent proximity fed gap-coupled half equilateral triangular microstrip antennas yields bandwidth of more 700 MHz (~47%). The bandwidth of proximity fed equilateral triangular and half equilateral triangular microstrip antennas is further increased by using gap-coupled configurations with equal and unequal dimensions compact half equilateral microstrip antennas. These gap-coupled configurations yields bandwidth of more than 800 MHz (>50%) with broadside radiation pattern and peak gain of nearly 8 dBi.

What will blue compact dwarf galaxies evolve into?

We present and analyse the photometric properties of a nearly complete sample of blue compact dwarf (BCD) and irregular galaxies in the Virgo cluster from multi-band SDSS images. Our study intends to shed light on the ongoing debate of whether a structural evolution from present-day star-forming dwarf galaxies in a cluster environment into ordinary early-type dwarf galaxies is possible based on the structural properties. For this purpose, we decompose the surface brightness profiles of the BCDs into the luminosity contribution of the starburst component and that of their underlying low surface brightness (LSB) host. The latter dominates the stellar mass of the BCD. We find that the LSB-components of the Virgo BCDs are structurally compatible with the more compact half of the Virgo early-type dwarfs, except for a few extreme BCDs. Thus, after termination of starburst activity, the BCDs will presumably fade into galaxies that are structurally similar to ordinary early-type dwarfs. In contrast, the irregulars are more diffuse than the BCDs and are structurally similar to the more diffuse half of the Virgo early-type dwarfs. Therefore, the present-day Virgo irregulars are not simply non-starbursting BCDs. If starbursts in cluster BCDs are transient phenomena with a duration of ~100 Myr or less, during which the galaxies could not travel more than ~100 kpc, then a substantial number of non-starbursting counterparts of these systems must populate the same spatial volume, namely the Virgo cluster outskirts. The majority of them would have to be early-type dwarfs, based on the abundance of different galaxy types with similar colours and structural parameters to the LSB-components of the BCDs. However, most Virgo BCDs have redder LSB-host colours and a less prominent starburst than typical field BCDs, preventing a robust conclusion on possible oscillations between BCDs and early-type dwarfs.

A Compact Half Select Disturb Free Static Random Access Memory Cell with Stacked Vertical Metal–Oxide–Semiconductor Field-Effect Transistor

In this paper, a half select disturb free compact static random access memory (SRAM) cell with the stacked vertical metal–oxide–semiconductor field-effect transistor (MOSFET) is proposed, and the impacts on its cell size, stability and speed performance are evaluated. The proposed SRAM cell has a small cell size, which is 67% of the conventional eight-transistor (8T) SRAM cell, because of its stacked vertical MOSFET structure. It realizes a half select disturb free SRAM operation; therefore, a larger static noise margin of 5.9 times is achieved in comparison with the conventional 8T SRAM cell. It suppresses the degradation of the write margin, thus its write margin is 84.2% of the conventional 8T SRAM cell. Furthermore, it suppresses the degradation of the write time by 39% (0.249 ns). The proposed compact SRAM cell with the stacked vertical MOSFET is a suitable SRAM cell with a small cell size, immunity to the half select disturb, wide write margin and fast write time.

A Compact Half Select Disturb Free Static Random Access Memory Cell with Stacked Vertical Metal–Oxide–Semiconductor Field-Effect Transistor

In this paper, a half select disturb free compact static random access memory (SRAM) cell with the stacked vertical metal–oxide–semiconductor field-effect transistor (MOSFET) is proposed, and the impacts on its cell size, stability and speed performance are evaluated. The proposed SRAM cell has a small cell size, which is 67% of the conventional eight-transistor (8T) SRAM cell, because of its stacked vertical MOSFET structure. It realizes a half select disturb free SRAM operation; therefore, a larger static noise margin of 5.9 times is achieved in comparison with the conventional 8T SRAM cell. It suppresses the degradation of the write margin, thus its write margin is 84.2% of the conventional 8T SRAM cell. Furthermore, it suppresses the degradation of the write time by 39% (0.249 ns). The proposed compact SRAM cell with the stacked vertical MOSFET is a suitable SRAM cell with a small cell size, immunity to the half select disturb, wide write margin and fast write time.

Spatial variation in soil compaction, and the burrowing activity of the earthworm Aporrectodea caliginosa

The effects of soil compaction on earthworm ( Aporrectodea caliginosa nocturna) activity were studied using pot experiments. Two compaction pressures were used when packing the pots; loose soil was packed by applying a pressure of 96 kPa, and compact soil was packed using a compaction pressure of 386 kPa. “Split pots” which contained both loose and compact soil were also used. In split pots peripheral burrows (those next to the pot wall), were generally longer in the loose half of the pot than they were in the compact half. This implies that earthworms preferred the loose soil. An important finding was that peripheral burrows in the split pots were longer than those made in pots packed uniformly with either loose or compact soil. Our data suggest that the increase in activity in split pots is a response to spatial variation in soil compaction. In the split pots the earthworms tended to avoid the compact half, and we discuss how the avoidance response in the split pots may have increased the proportion of burrows in these pots that were peripheral.

Compact Hermitian surfaces and isotropic curvature

It is shown that on a Kahler surface the non-negativity (resp. non-positivity) of the isotropic curvature is implied by the non-negativity (resp. non-positivity) of the holomorphic bisectional curvature. The compact Hermitian surfaces of non-negative isotropic curvature are described. The full list of compact half conformally flat Hermitian surfaces of non-positive isotropic curvature is also given.

Design of Radio Frequency Systiem for the Riken Separated Sector Cyclotron

The radio-frequency (RF) system of the RIKEN SSC (K=540) is required to work in a frequency range of 20 to 45 MHz and to generate the maximum acceleration voltage 250 kV. A new movable box type variable frequency resonator is designed for that purpose. This resonator is a compact half wave length coaxial type ((2.1 m(H) x 3.5 m(W) x 1.6 m(D)). The delta shaped dee whose radial length is 2.7 m is supported in median plane by vertical stems from the both sides. The resonant frequency is varied by moving the boxes surrounding the stems. The performance of this resonator is studied on a one-fourth scale model. The maximum power loss is estimated to be 250 kW for the required dee voltages and the radially increasing voltage distributions are obtained. The RF power is fed into the resonator through a 50 ..cap omega.. coaxial feeder line ( about 1.8 m length) which is coupled with the resonator in good impedance matching by means of a variable capacitive coupler. The final amplifier is of grounded grid configuration; load resistance matching is made by a variable capacitor inserted in series at its output port. The final amplifier and its components aremore » studied on full sized models. The result shows the movable box type resonator and power amplifier satisfy the design aim.« less