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Novel back-illuminated modified uni-traveling- carrier photodiodes (MUTC-PDs) are reported to demonstrate wide bandwidth and high output power performance at D-band (110–170 GHz) regime. A comprehensive design model is employed to predict and tune the frequency response by incorporating coplanar waveguides (CPWs) with different inductive peaking effects. As a demonstration, 4.5-μm-diameter photodiodes with two types of CPWs are fabricated to exhibit different frequency response profiles. Both PDs exhibit a 3-dB bandwidth over 150 GHz and the measured frequency responses are in excellent agreement with simulations. Thanks to the proper design of the CPW electrodes, the two PDs exhibit an output power roll-off of only 4.3 dB and 4.8 dB from dc to 170 GHz, respectively, and high saturation performance is maintained over the broadband frequency range of 130–170 GHz.

The potential of higher band millimeter waves for characterization of different types of breast tissues based on the dielectric contrast between normal and malignant tissues has been reported. Lowcost phantom samples of normal and malignant tissues have been prepared using naturally occuring components, i.e., agar, water, olive oil and pectin. Waveguide probe based calibration technique was used to extract the complex permittivities of the twocomponent (wateragar) and threecomponent (wateroilagar) phantoms. The twocomponent phantoms were used to study the change in the dielectric properties of phantom with change in agar concentration. Water, agar and varying proportions of oil were used to develop threecomponent phantom mixtures to mimic the dielectric properties of fat, fibrous and malignant breast tissues. Finally, the reflection and transmission properties of tissue mimicking phantoms were tested using the waveguide probe calibration based measurement setup. The difference in the S parameters between the three types of phantoms demonstrate the potential utility of D band based data acquisition setups for tumor margin assessment applications.

High-loaded oxygen reduction reaction (ORR) Pt intermetallic compounds with high performance expression under PEMFC operating conditions are prerequisite for practical application. Nevertheless, high metal-loading would lead to the severe agglomeration and nonuniformity of nanoparticles, imposing an enormous challenge on efficient synthesis. Herein we present a cobalt oxide aided structural evolution strategy to controllably synthesize high-loaded (44.7 wt%) sub-6 nm Pt1Co1 intermetallic compound with Pt-rich shell (Pt1Co1-IMC@Pt). Experiments and theory explicitly reveal that the ordered arrangement of Pt-Co atoms endows surface Pt with lowered d band centre and enhanced oxidation-resistance of Pt/Co sites, thus simultaneously boosting the ORR activity and durability. The preeminent intrinsic ORR activity on an optimized catalyst reaches a mass activity as high as 0.53 A mg(Pt)-1 @0.90V/RHE (MA@0.9 V) in rotating disk electrode measurement. PEMFCs with such a catalyst deliver the record-high power density (2.30/1.23 Wcm-2 under H2-air/O2 conditions at 80 oC) and extraordinary stability, ranking the highest fuel cell performance among the Pt-based electrocatalysts. Significantly, the MA@0.9 V calculated from fuel cell attains 0.46 A mg(Pt)-1, exceeding the 2020 DOE target (0.44 A mg(Pt)-1) and very close to the intrinsic value, definitely confirming the superiority of high-loaded Pt1Co1-IMC@Pt/C in activity expression under fuel cell conditions. This study paves a new way for the future practical application of low-Pt catalysts in PEMFCs.

This letter presents a four-way power-combined $D$ -band silicon–germanium (SiGe) power amplifier (PA), which simultaneously achieves high output power and high efficiency. A 4-to-1 planar coupled-line Wilkinson combiner is used, which has low loss and provides broadband impedance transformation. The PA is designed in a 90-nm SiGe BiCMOS technology platform and operates over a bandwidth of 110–145 GHz, with 18.2 dB of gain. The design achieves a peak output power of 21.9 dBm at 130 GHz, with a power-added efficiency (PAE) of 12.5%. The PA maintains greater than 20-dBm output power with greater than 8.7% PAE, from 115 to 140 GHz. This work demonstrates the first silicon-based $D$ -band PA, which simultaneously achieves greater than 20-dBm output power and 10% PAE.

In this letter, a wideband substrate integrated waveguide (SIW) based slot antenna is designed for D -band applications. A wideband response is attributed to the merging of closely lying six resonance frequencies. Two of them at frequencies of 114.25 GHz and 134.75 GHz signifies the excitation of TE $_{310}$ and TE $_{120}$ modes, respectively. The modes at 124 GHz and 144 GHz are identified as hybrid modes that are formed from the combination of TE $_{310}$ –TE $_{120}$ and TE $_{120}$ –TE $_{220}$ modes, respectively. The upper two resonances at the frequencies of 154 GHz and 160 GHz occur due to TE $_{220}$ –TE $_{320}$ based hybrid modes. A two-step wideband WR6-SIW transition is also designed and integrated with the antenna for measurement purpose. In the first step, the three-section Chebyshev transition is developed to match the impedance of standard WR6 with a rectangular waveguide (RWG) of the same height as that of the PCB. In the second step, the RWG is matched with SIW using a dielectric extension. The final antenna with transition is simulated and measured. A wide $-$ 10 dB impedance bandwidth for $|S_{11}| \leq -$ 10 dB of 42.86% (110–170 GHz) is obtained. The gain and radiation measurements were also performed after constructing an in-house measurement system.

International audience; A low-cost dual linearly-polarized transmitarray antenna (TA) is presented for 5G and beyond networks at D-band. This TA is made of 40 40 unit-cells (UCs) and is illuminated by a stepped feed horn with a F/D ratio equal to 0.75. The flat lens panel is based on UCs with six different phase states at the center frequency of 150 GHz (thus leading in average to a 2-bit phase quantization and 0.7-dB insertion loss from 130 to 175 GHz). Each UC is made of only three metal layers and does not include any via connection to guaranty performance robustness with respect to fabrication dispersions. The measured1-dB and 3-dB TA gain bandwidths equal 16.8% and 19.8%, respectively, with a peak gain of 32 dBi, corresponding to an aperture efficiency of 32% at 150 GHz. The measured sidelobe and cross-polarization levels in E and H planes remain below -21 and -37 dB, respectively. An excellent agreement between measured and simulated radiation patterns was observed.

A considerable amount of platinum (Pt) is required to ensure an adequate rate for oxygen reduction reactions (ORR) in fuel cells and metal-air batteries. Thus, the implementation of atomic Pt catalysts holds promise for minimizing the contents of Pt. In this contribution, atomic Pt sites with nitrogen (N) and phosphorus (P) co-coordination on carbon matrix (PtNPC) are conceptually predicted and experimentally developed to alter the d -band center of Pt, thereby promoting the intrinsic ORR activity. The PtNPC with a record-low Pt content (~0.026 wt%) consequently shows a benchmark-comparable activity for ORR with an onset of 1.0 V RHE and half-wave potential of 0.85 V RHE . It also features a high stability in 15,000-cycle tests and a superior turnover frequency of 6.80 s -1 at 0.9 V RHE . Damjanovic kinetics analysis reveals a tuned ORR kinetics of PtNPC from mixed 2/4-electron to predominate 4-electron route. It is discovered that coordinated P species significantly shifts d -band center of Pt atoms, accounting for the exceptional performance of PtNPC.

This letter presents a ring-shaped $E$ -plane filtering coupler working at 150 GHz with high performance. The coupler is based on cavity resonators. Unlike the conventional ones, the four resonators in this coupler are all bent along their length direction and connected end to end, forming a closed circle. By adjusting the radius of the circle, three of the resonators work on TE101 mode while the other is on TE102 mode. The coupler can be split through $E$ -plane and the measured response of the coupler has an excellent agreement with the simulation, with a low amplitude imbalance of 0.31 dB, insertion loss of 0.12–0.46 dB, and over 20-dB return loss and isolation.

This article presents two kinds of low-cost antennas for $D$ -band short-distance wireless communication applications. Both the antennas are excited by a substrate integrated waveguide (SIW) feed line based on the printed circuit board (PCB) process. The first type is a stainless-steel-based horn antenna, fabricated by electric-discharging machining (EDM) process and selective laser melting (SLM) 3-D printing, respectively, for reducing cost. To integrate the horn antennas with the SIW feed line, a wideband transition structure from SIW to the rectangular waveguide is designed by suppressing higher order eigenmodes. The experimental data show that the integrated horn antenna can achieve 18.9% (129.5–156.5 GHz) −10 dB impedance bandwidth and a peak gain of 15.46 dBi. The second type of antenna is a single-layer rectangular patch antenna fed by SIW. By locally widening the SIW feed line to generate an equivalent shunt capacitance instead of using complex resonators, a wide impedance bandwidth can be realized. The measured −10 dB impedance bandwidth and the peak gain of the patch antenna are 20.8% (125.3–154.4 GHz) and 7.26 dBi, respectively. The two proposed antennas can provide comparable performance for different application requirements under the premise of a low fabrication cost.

This work focuses on the impact of the build orientation on additively manufactured waveguide-based hybrid couplers for D-band frequency range and relates it to other sources of uncertainty within the overall manufacturing process and measurement instrumentation for the D-band frequency range. The designed specimens are first printed from UV curable photopolymer resin and subsequently metal coated by an electroless silver plating process, which in turn is improved by making use of the slotted waveguide approach. Although the requirements toward geometrical precision to achieve phase errors below 10° are in an order of 0.1 mm, a desktop grade DLP printer is utilized in this work in order to point out the prospects and limitations of additive manufacturing. Furthermore, waveguide paths with bends are part of the model and their impact on the measured attenuation is estimated explicitly.Despite this narrow field of tolerances, one specimen could have been realized, which achieves a measured output magnitude imbalance of 0.7 dB over the frequency range from 120 to 155 GHz while at the same time exhibiting a phase deviation of only

The D-band (110∼170 GHz) thin film microstrip line (TFML) with easy integration, low loss, and easy fabrication is presented in this work. It is composed of copper (Cu) signal line on the top layer, ultra-thin Benzocyclobutene (BCB) dielectric on the interlayer and Cu ground plate on the bottom. This study presents the calculation formulas, extraction methods, reduction solutions of metal loss, dielectric loss, and radiation loss. The calculation results well agree with the simulation results. Metal loss caused by skin effect and surface roughness is the main part of loss, accounting for 89%. The introduced micro-electro-mechanical-systems (MEMS) process could precisely manufacture samples in batches. The tested loss after thru-reflect-line (TRL) de-embedding is 0.6 dB/mm, which is higher than the simulated loss of 0.4 dB/mm. The simulated loss corrected after considering the roughness effect has good agreement with the tested loss. The proposed TFML and its loss analysis help to design planar passive devices with low loss at D band.

Semiempirical energy relations provide a means of estimating thermodynamic properties. Specifically, linear scaling relationships (LSRs) and Bronsted–Evans–Polanyi (BEP) relationships correlate ads...

This work reports in first time a 100-Gb/s, ultra-low noise, variable gain multi-stagger tuned transimpedance amplifier (VGMST-TIA) over the D-band performance. The whole work is binding into two phases. The first phase involves the modeling and characterization of graphene field-effect transistor (GFET) with an optimized transition frequency of operation. While in the second phase, a TIA design employs a T-shaped symmetrical L-R network at the input, which mitigates the effect of photo diode capacitance and achieves a D-band of operation. The proposed work uses a VGMST to establish TIA, which realizes optimum noise performance. The high gain 3-stage VGMST-TIA effectively minimizes the white noise and illustrates a sharp out-of-band roll-off to achieve considerable noise reduction at high frequencies. The active feedback mechanism controls the transimpedance gain by tuning the control voltage which results better group delay. Besides, an L-C circuit is employed at the output to enhance bandwidth. The full TIA is implemented and fabricated using a commercial nano-manufacturing 9-nm graphene film FET on a silicon wafer using 0.065-μm process. The TIA achieves a flat transimpedance gain of 61.2 dBΩ with ± 9 ps group delay variation over the entire bandwidth. The proposed TIA measured an impedance bandwidth of 0.2 THz with ultra-low input-referred noise current density of 2.03 pA/√Hz. The TIA supports a 100-Gb/s data transmission due to large bandwidth; therefore, a bit-error-rate (BER) less than 10−12 is achieved. The chip occupies an area of 0.92 * 1.34 mm2 while consuming power of 21 mW under supply of 1.8 V.

This letter presents a D-band (110 to 170 GHz) transmit–receive module in 0.13- $\mu \text{m}$ silicon–germanium (SiGe) BiCMOS for phased-array applications. The module includes single-pole double throw (SPDT) switches, a low noise amplifier (LNA), a power amplifier (PA), and two variable gain amplifiers (VGAs). A broadband quarter-wave SPDT is designed with power handling capacity of 17 dBm and a state-of-the-art insertion loss of 2 dB at 140 GHz. The three-stage cascode LNA and PA and the two-stage phase-compensated VGA cover the entire D-band. In the receive mode, the module has a measured peak gain of 28.3 dB with a 3-dB bandwidth (BW) of 110–170 GHz, along with a minimum noise figure (NF) of 9 dB (at 120 GHz) and an IP1dB of −21 dBm. In the transmit mode, the peak gain is 22.4 dB within a 3-dB BW of 113–170 GHz, while the OP1dB is 7 dBm and the $\text{P}_{\mathrm{ sat}}~9.5$ dBm at 140 GHz.

Single atom catalysts (SACs) have received much attention in the nitrogen reduction reaction (NRR) field due to their high atomic utilization and controllable electronic state regulation. It is attractive to explore the mechanism for regulating the electronic state of the active center of single-atom catalysts. Herein, we propose a new regulation mechanism by applying a strain that can change the coordination bond length of Cr–N and quantitatively regulate the electronic state of the active center in Cr-SACs. Based on this mechanism, we achieve an ultra-low 0.174 V over-potential for the NRR in the single Cr-embedded nitrogen-doped graphene (CrN3@graphene) by applying lattice stretch of 2.5% compared to the pristine CrN3@graphene. Computational results show that the d band center, the Cr–N anti-bonding orbital and the spin-polarization state of the single Cr atom can be adjusted by tuning the coordination length of Cr–3N. The applied lattice stretch of 2.5% can transform the spin-polarization state of the single Cr atom from a high-spin-polarization state to low-spin-polarization. This conversion weakened the adsorption capacity of N2 for CrN3@graphene and finally achieved an ultra-low over-potential. Our findings open up a new path of NH3 production by exploiting strained SACs under ambient conditions.

This letter presents a novel approach for packaging millimeter-wave (mmW) and terahertz (THz) circuits. The proposed technique relies on using an on-chip coupling structure that couples the signal to a quarter-wavelength cavity, which in turn couples to either a waveguide (WG) or another chip. The solution also uses a periodic electromagnetic bandgap (EBG) structure that controls the electromagnetic wave and prevents field leakage in undesired directions. The proposed solution is fabricated and demonstrated at the $D$ -band (110–170 GHz), and the measurement results show that it achieves a minimum insertion loss of 0.8 and a 3-dB bandwidth extending from 124 to 161 GHz. The proposed approach does not require any galvanic contacts and can be used for packaging integrated circuits in WG modules as well as for chip-to-chip communication.

Regenerative energy replacing CO2-releasing fossil fuels has drawn widespread attention in wind/solar energy storage and conversion. In particular, CO2 reduction to valuable chemicals using renewable energy is attractive and alleviates global warming. Cu is prominent for CO2 reduction to derive multi-carbon products, such as ethylene. However, the productivity, energy efficiency, and cost-effectiveness of Cu-based electrocatalysts remain unsatisfactory in meeting industrial requirements. Hence, ultrathin CuCo nanocrystals are exploited for CO2 reduction to ethylene, delivering a high faradaic efficiency of 81.3% at a potential of −1.5 V vs. reversible hydrogen electrode (RHE). Tailoring the d-band states and synergistic cooperation between Cu and Co are significant to boost activity via controlling the intermediate binding energy and lowering the reaction energy barriers.

In the present work, we have explored the passivation mechanism of Graphene based schottky junction photodiodes. The graphene sheet was developed by low cost camphor as a solid source of carbon to avoid toxic gaseous carbon precursor. Moreover, coupling with Si or SiNWAs makes it a promising candidate for large-scale and cost effective optoelectronic application. The 8–10 μm nanowire arrays in the present case, demonstrates excellent optical light trapping properties with the reflectance of 4% over a wide range of wavelength (200–1200 nm). On the other hand, large scale graphene sheet developed by camphor contributes no defect D band at (∼1360 cm−1) with 2D/G ratio of 2.43. It is found that, the performance of Gr/SiNWAs schottky junction is restricted by strong carrier recombination and relative low schottky barrier height (SBH). We have modified the surfaces of nanowires by H-passivation in order to improve the electrical performance of the device. Passivation of SiNWAs showed the capability to effectively suppress the surface carrier recombination upto certain extent, leading to a more electron transfer and an improvement in the JSC values from 0.3 mA/cm2 to 2.7 mA/cm2 typically at −1 V.

The quality of Li-ion batteries is highly related to the crystallinity of the graphite used in their electrodes. Therefore, the development of two-dimensional detection equipment for evaluating the integrity of graphite electrodes is critical. In this study, a triaxial scanning platform was developed for Raman spectroscopy. Two-dimensional Raman mapping of the defects (D band) and stacking (2D band) of graphite electrodes was performed to determine atomic-level variations caused by charging. Through Raman mapping, the effects of constant-current–constant-voltage (CC–CV) and CC–reFLEX fast charging were compared. The graphite damage from CC–reFLEX fast charging was less extensive than that from CC–CV charging. Furthermore, investigations using the triaxial platform revealed that the graphite on a curved electrode exhibited disordered stacking after several charging–discharging cycles. This phenomenon creates safety concerns.

We demonstrate anomalous reflectors at 140 GHz for the application of 6G communication coverage expansion. The reflectors are designed on cyclo-olefin polymer (COP) substrates on the basis of measured complex permittivity and conductivity at millimeter frequencies obtained with the balanced-type circular disk resonator method. From full-wave simulations, we confirm that nearly perfect anomalous reflection characteristics are realized with suppressed parasitic reflections in undesired directions. The simulated efficiencies excluding the material losses of the reflectors designed with the reflection angle $\theta _{\mathrm {R}}={30}^\circ $ , 45°, 60°, and 75° are 99.5%, 98.9%, 99.7%, and 99.8%, respectively. In addition, we fabricate the designed reflectors on the COP substrates and experimentally evaluate their anomalous reflection performances. The measured overall efficiencies of the reflectors with $\theta _{\mathrm {R}}={45}^\circ $ , 60°, and 75° are 88.0%, 83.6%, and 81.6%, respectively. This is the first demonstration of highly efficient anomalous reflectors in the D-band.

This letter presents a dual-polarized wideband plate array antenna in D-band for future fixed high-capacity wireless communication. To achieve the high polarization isolation and wideband operation at the same time, a two-stage multimode cavity is introduced, consisting of a polarization isolation cavity and a cascaded dividing cavity. They are combined to optimize and improve the bandwidth of the dual-polarized antenna array. The TE210 and TE120 degenerate modes are selected to resonate in the cavity. They can be used to generate two orthogonal linear polarization modes with the extremely low cross polarization after cascading four integrated horns with a proper placement. To validate the design, an 8 × 8 element array is fabricated by the diffusion bonding of laminated thin copper plates technology. The gain is more than 24.5 dBi from 130 to 149 GHz. The isolation between two channels is higher than 50 dB and the cross polarization level is below −45 dB over the whole band.

The Raman spectra of multiwall (bamboo-type) carbon nanotubes implanted with nitrogen have been investigated under excitation by different lasers with wavelengths λ = 405, 532, 633, and 785 nm in a wide frequency range from 50 to 4500 cm–1. The spectra included intense bands corresponding to the G and D modes and their overtone transitions. The microscopic mechanism of the frequency shift of the D band of carbon nanotube Raman scattering with a change in the excitation wavelength is analyzed.

In this study, we investigated the hydrogen evolution reaction (HER) on the (101) facet of pristine and W-doped CoP using the density functional theory. Two types of Co atoms are identified on the catalyst surface: the Co atoms that present the higher d band center are marked as valid sites, whereas the others are marked as invalid sites owing to their weaker H adsorption ability. It is further revealed that W-doping can decrease the d band center of the surface Co atoms, which is beneficial for the HER; however the exposure to W weakens the desorption of H. To address the strong adsorption effect of W, the doping sites and dopant content are analyzed, and the results indicate that 8.4 wt% W doping at the invalid surface Co sites is preferred; moreover, the optimal W content increases to 16.8 wt% when W is inserted into the subsurface. The effect of W doping is weakened when the doping site is far away from the surface.

High-energy ball milling (HEBM) combined with powder metallurgy route was used to fabricate carbon nanotube (CNT) reinforced 7055Al composites. Two powder morphology evolution processes (HEBM-1 and HEBM-2) were designed to investigate the dispersion and damage of CNTs during HEBM process. HEBM-1 evolution process involved powder flattening, cold-welding and fracture, while HEBM-2 evolution process consisted of powder flattening and fracture. For HEBM-1, the repetitive fracture and cold-welding process was effective for dispersing CNTs. However, the powder flattening process in HEBM-2 was unsuccessful in dispersing CNTs due to two reasons: (1) the thickness of flaky Al powders exceeded the critical value, and (2) the clustered CNTs embedded in flaky Al powders could not be unravelled. Because of the broadening of D band and the appearance of a new defect-related D’ band, product of ID/IG and full width half maximum of D band, rather than ID/IG, was used to evaluate the actual damage of CNTs. It indicates that the damage of CNTs was severe in powder flattening and fracture stages, while the damage of CNTs was small in powder cold-welding stage.

A millimeter-wave (mm-wave) voltage-controlled inductor (VCI) that is based on a series inductor–capacitor tank and that achieves large ratios of maximum to minimum inductance is proposed. For demonstration, a VCI with an inductance ratio of 4 is employed in a 22-nm CMOS silicon on insulator (SOI) Colpitts third-order-harmonic-extracted injection-locked (IL) oscillator (ILO) operating from 112.5 to 135 GHz. The ILO dc power consumption is 13 mW with a 1.2-V supply but is reduced to 5.6 mW with a 0.8-V supply when a 2-V back-gate voltage is applied. Due to the proposed VCI, the core of the mm-wave ILO occupies only 0.018 mm 2, the tunable operating range is ≥16%, and the added phase noise (PN) (~10 dB) is close to the theoretical prediction (20log(3) dB).

Interactions between epitaxial graphene grown on Si- and C-faces were investigated using Raman imaging and tip-enhanced Raman scattering (TERS). In the TERS spectrum, which has a spatial resolution exceeding the diffraction limit, a D band was observed not from graphene surface, but from the edges of the epitaxial graphene ribbons without a buffer layer, which interacts with SiC on the Si-face. In contrast, for a graphene micro-island on the C-face, the D band disappeared even on the edges where the C atoms were arranged in armchair configurations. The disappearance of the edge chirality via combination between the C atoms and SiC on the C-face is responsible for this phenomenon. The TERS signals from the C-face were weaker than those from the Si-face without the buffer layer. On the Si-face with a buffer layer, the graphene TERS signal was hardly observed. TERS enhancement was suppressed by interactions on the edges or by the buffer layer between the SiC and graphene on the C- or Si-face, respectively.

The rational design of oxygen evolution reaction (OER) catalysts from the perspective of electronic structure is highly desirable to optimize electrocatalytic activity. Monometallic phosphides such...

This letter describes a $D$ -band antiparallel diode-connected nMOS-transistor-pair frequency tripler that is capable of operating over 27.8% 5-dB bandwidth (from 93 to 123 GHz) and achieves −16-dBm output power. The back-gate voltage is used to control the nonlinearity of the nMOS devices and can be tuned to optimize output power and conversion loss, for a range of input power levels. The tripler is implemented in the 22-nm CMOS SOI process and avoids the use of Schottky diodes.

This article presents a compact 150-GHz transmitter with 12-dBm $P_{\mathrm{ sat}}$ and 17-dB conversion gain. This $D$ -band transmitter is composed of a frequency doubler, a micromixer, a two-stage $g_{m}$ -boosting power amplifier (PA), and an on-chip dielectric resonate (DR) antenna. At sub-terahertz, the output power and the gain are the limiting factors for the transmitter’s performance. In this work, $g_{m}$ -boosting topology is implemented to achieve the 17-dB gain by taking advantage of the base inductor without sacrificing the PA’s stability. The output power of the 150-GHz PA is enhanced by the proposed phase compensation method. In this proposed method, an auxiliary inductor is added for adjusting the phase difference to decrease the introduced loss from power combining and matching networks. The imbalance at the LO port is also reduced by the proposed capacitor and the resistor compensation method. From 140 to 160 GHz, the transmitter delivers more than 8-dBm output power, with the maximum $P_{\mathrm{ sat}}$ of 12 dBm at 148 GHz. This transmitter exhibits a conversion gain of 17 dB and an output 1-dB compression point ( ${\mathrm{ OP}}_{1~{\mathrm{ dB}}}$ ) of 11.4 dBm. The transmitter exhibits the highest output power, the highest ${\mathrm{ OP}}_{1~{\mathrm{ dB}}}$ , competitive conversion gain, and bandwidth among any silicon-based transmitters in $D$ -band, to the best of our knowledge.

A D-band low-loss mixed-mode filter with high selectivity is proposed and analyzed in this article. The transverse quintuplet/triple topology has been employed in the design with coupled overmode cavities using the TE $_{\mathrm {2N,1,0}}$ modes ( $N = 2,3,4, \ldots $ ) and TE $_{\mathrm {2N,1,0}}$ -like modes. Two transmission zeros (TZs) are generated in the upper and lower stopbands. The fractional bandwidth (FBW) and positions of the TZs can be flexibly designed by properly selecting the geometries of the proposed overmode cavity, which determines the frequencies of all resonating modes. To improve the frequency selectivity, multiple coupled overmode cavities, which have different spurious responses and TZs distributions, are cascaded for the designed filter. For demonstration purposes, two types of filter architectures are proposed for two D-band mixed-mode bandpass filters, respectively, which shows the design flexibility of the proposed method. The first filter is realized by cascading multiple overmode cavities through waveguide sections, and the second filter is realized by cascading overmode cavities through slots. Experiments are carried out to verify the second filter with TZs. The measured FBW3 dB is 17.18% from 128.11 to 152.19 GHz, the minimum insertion loss is around 0.33 dB, and the measured rectangle coefficient (BW40 dB/BW3 dB) is about 1.38. The measured results agree well with the designed ones, which verifies the proposed method. The proposed filter can be a good candidate for millimeter-wave and terahertz systems.

The effect of filling of 3-d orbitals on structural, electronic, magnetic and optical properties of TMScO3 perovskite, where TM is 3-d series from Ti to Zn, is studied through the Density Functional Theory (DFT) utilizing full potential linearized augmented plane wave (FP-LAPW) method using mBJ approximation. Filling the outer “d” shells of TM atoms in TMScO3 changes the compounds behavior as TM atoms changes from Ti to Zn properties of materials. The total magnetic moment (Mt) increases as the 3-d orbitals filling increases, its maximum value occurs for MnScO3 perovskite as Mn is in the middle of the 3-d transition series. Beyond this Mt tends to decrease with a minimum value for ZnScO3. All compounds show half metallicity behavior (except for TiScO3 which shows metallic behavior). The rest of properties (lattice constant, energy band gaps Eg and optical properties) are also affected by 3d-shell filling.

A wideband air-filled plate array antenna with multistage impedance matching operated in $D$ -band is proposed in this article. To achieve the wide bandwidth, three stages of impedance matching are introduced in the $2\times 2$ subarray, including the step-profiled horn element, the step-profiled power divider cavity with two resonant points, and a modified E-plane bend transition. The integrated step-profiled horn with simple configuration can realize broadband matching. Wideband T-junctions are combined together to form a corporate feeding network. Essential matching pins are introduced to break through the upper bandwidth restriction of the feeding network. In addition, the square aperture shape of the horn element and the air-filled feeding structure contribute to the high radiation efficiency of the proposed array. To satisfy the fabrication tolerance, the MEMS micromachining technology with a high etching precision is utilized. The experimental results show a wide 1 dB down gain bandwidth of 23.54%. The maximum gain is 33.24 dBi and the peak efficiency is 70.91%.

The catalytic activity of the catalyst closely depends on its electronic structure, but the relationship between electronic structure and the catalytic activity in the ammonia borane (NH3BH3, AB) c...

The interwall interactions in multi-walled carbon nanotubes (MWNTs), which are associated with the number of walls and may vary even at nanoscale, are important to investigate as they strongly infl...

This paper reports the design and characterization of a D-band front-end receiver, implemented in a 0.13- ${\mu {m}}$ SiGe BiCMOS technology, for use in a direct-detection-based Dicke radiometer architecture. The peak responsivity of the Dicke radiometer is 688 MV/W at 130 GHz, and its minimum value is about 82.6 MV/W at 170 GHz. The Dicke switching frequency is 10 kHz. The noise equivalent power of the Dicke radiometer remains below $20\textit {fW/H}{z}^{\text {1/2}}$ at the frequency range of 110–155 GHz, and its minimum value is about $9.3~\textit {fW/H}{z}^{\text {1/2}}$ at 130 GHz. The implemented radiometer achieves an NETD of 0.13K for a back-end integration time of 30ms. Its total chip area is approximately 1.7mm2, and the overall quiescent DC power consumption is 33.8 mW. To the authors’ best knowledge, the implemented Dicke radiometer achieves the best NETD in the literature.

This article presents a packaging technique for monolithic microwave integrated circuits (MMIC) demonstrated in a fully integrated receiver (Rx) module at the D -band (110–170 GHz). The solution consists of an MMIC-to-waveguide transition realized using an on-chip probe mounted in the E -plane of a split-block waveguide module. An artificial magnetic conductor structure is implemented to suppress cavity modes and achieve better coupling from the waveguide to the probe. The transition's performance is experimentally verified using a back-to-back test chip, and measurement results show that the proposed packaging solution achieves a low insertion loss of only 0.7 dB and covers a very wide frequency range extending from 105 to 175 GHz. The proposed transition is also integrated with an in-phase/quadrature-phase (I/Q) Rx on the same chip. The Rx is realized in a 250-nm indium phosphide double heterojunction bipolar transistor technology and consists of a low-noise amplifier, an I/Q mixer, and a frequency tripler. Measurement results show that the Rx module achieves an average conversion gain of 23 dB across the frequency range of 110–145 GHz and has an average noise figure of 10.6 dB. The Rx MMIC has a dc power consumption of 440 mW and occupies an area of 1.6 × 1.6 mm2. This article addresses one of the main challenges in systems operating above 100 GHz and presents a fully integrated packaging solution that suits large integrated circuits and does not require any galvanic contacts nor impose any limitations on MMIC dimensions.

A 130 GHz fully-integrated fundamental-frequency transmitter (TX) module with 4.4 dBm single-ended measured output power in a 130 nm SiGe technology is presented. The transmitter achieves in measurement a phase noise of −88 dBc/Hz at 1 MHz offset frequency from a 130 GHz carrier and a tuning range of 17 GHz. Its relatively compact size, low power consumption and high output power, enables the TX module to be integrated into more complex D-Band transceiver modules for radar and imaging applications. Due to the available measurement equipment, it was only possible to measure the output power single-ended. The measured single-ended output power is 4.4 dBm. This corresponds well to a simulated maximum differential output power of 8.1 dBm. To the best of the author’s knowledge, the presented chip exhibits one of the highest output power for fundamental-frequency TX modules among the recently reported state-of-the art chips in this frequency range.

Summary Anisotropies in electronic transportations conventionally originate from the nature of low symmetries in crystal structures and were not anticipated for perovskite oxides with crystal asymmetries much smaller than, e.g., van der Waals or topological crystal. Beyond conventional expectations, here we demonstrate pronounced anisotropies in the inter-band Coulomb repulsion-dominated electronic transportation behaviors in the low-dimensional perovskite family of rare-earth nickelates (ReNiO3). The in-plane orbital entropy associated to the in-plane symmetry of the NiO6 octahedron within ReNiO3 causes intrinsic anisotropies for the gradual orbital transition with temperature to regulate their thermistor transportations. Extrinsically imparting biaxial interfacial strains amplifies the anisotropies in the electronic transportation of ReNiO3. It unveils the overlooked role of orbital directionalities within low-dimensional correlated perovskites that triggers anisotropic transportations despite their higher crystal symmetries, and this introduces new freedoms to regulate their correlated transportations.

This paper presents a D-band (110–170 GHz) transmitter/receiver (Tx/Rx) chipset with end-fire on-chip antennas (OCAs) using 0.13-μm SiGe BiCMOS technology. The input LO signal frequency of the chipset is 31.25 GHz. A 62.5-GHz frequency doubler, a D-band 2nd-harmonic up-conversion mixer, a power amplifier (PA), and an end-fire antenna are integrated in the Tx. An end-fire antenna, a D-band low-noise amplifier (LNA), a 2nd-harmonic down-conversion mixer, and a 62.5-GHz frequency doubler are integrated in the Rx. The end-fire OCA has gain and efficiency of 4.1 dBi and 83%, respectively. Maximum measured effective isotropic radiation power (EIRP) of 9.2 dBm and conversion gain of 21 dB are achieved for the Tx and Rx, respectively. The Tx/Rx are packaged on PCBs through wire bonding and chip-to-chip wireless communication using 16QAM modulation with the data rate of 4 Gb/s is demonstrated. The DC power consumption of the whole chip is ~1150 mW, and the total chip size is 2 × 3.5 mm2.

In this letter, an ultrabroadband D-band wireless front-end receiver (RX) in 45-nm CMOS SOI is proposed. It achieves a noise figure of 8 dB, a gain of 16 dB, a 3-dB bandwidth of 25 GHz, and occupies a compact area of 2 mm2. To the best of our knowledge, for the first time, the required millimeter-wave local oscillator signal is generated on-chip. Furthermore, 108-Gb/s data-rate is demonstrated by receiving and demodulating a signal composed of $10\times 2.16$ GHz channels with −40-dBm average power and 64-QAM modulation. With a consumption of 200 mW from a 1-V voltage supply, the proposed RX achieves an energy efficiency of 1.8 pJ/bit.

We present novel three-layer $D$ -band linearly polarized transmitarrays entirely fabricated using standard printed circuit board (PCB) processes. Three flat lenses comprising 1600 elements are designed to generate broadside and scanned beams. All lenses are synthesized using eight unit cells (3 bit phase quantization). The combination of cells comprising probe-fed and aperture-coupled patches is proposed to overcome the design challenges due to technological constraints and achieve a wideband operation. The minimum design feature is $80~\mu \text{m}$ . The tradeoffs in the design of the feed illumination are analyzed using ad hoc numerical tools. A 10 dBi horn is eventually selected as source. The focal-to-diameter ( $F/D$ ) ratio is 0.75 for all lenses. The broadside array attains a peak gain of 33.0 dBi and a −1 dB relative gain bandwidth of 11.7%, i.e., wider than that of state-of-the-art designs, in the 100–300 GHz band, which use more complex technologies and larger focal distances. The performance of the proposed antenna technology demonstrates its potential for low-cost high-capacity wireless backhauls beyond 100 GHz.

This letter presents 1-stage and 2-stage compact D-band amplifiers with lumped-element matching networks implemented in 55 nm SiGe BiCMOS. To correctly account for the effects of a nonideal ground plane, i.e., reactances in current return paths, and coupling of inductors with nearby layout structures, a shielded 2-port, 4-terminal simulation strategy for inductors is proposed. Validated by measurements, the approach allows very accurate design of compact amplifiers in D-band. The 1-stage design proves 11.8 dB gain at 152 GHz and 17.9 GHz bandwidth in 0.031 mm2. With the 2-stage amplifier, featuring 20.1 dB gain at 150 GHz with 24.5 GHz bandwidth in 0.058 mm2, from $2\times $ to $5.7\times $ area reduction is demonstrated against similar SiGe amplifiers in the same frequency band.