Suspended Line Research Articles

A Low Phase Noise Oscillator Employing Weakly Coupled Cavities Using SISL Technology

A Ku-band low-phase noise oscillator, using a weakly coupled cavities resonator (WCCR), is proposed based on substrate-integrated suspended line (SISL) technology. Different from using a bandpass filter as the frequency selector for the feedback oscillator, we use weak coupling between resonators to form a resonator with a higher <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> . The theoretical analysis of weak coupling is derived. Under weak coupling, the equivalent <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> and insertion loss of the WCCR is given based on the mathematical deduction. The proposed WCCR can double the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> factor of the single cavity resonator (SCR) at the expense of an increase in the insertion loss. Two oscillators using WCCR and SCR are designed and fabricated to verify the theoretical analysis. The measured results show that the loaded <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> of WCCR increases by 80% compared with the SCR. The proposed oscillator has a low measured phase noise of −137.36 dBc/Hz at 1 MHz offset from the carrier frequency of 12.355 GHz, and the FOM is −207.12 dBc/Hz. Compared with the oscillator using SCR, the measured phase noise is improved by 5.13 dB. Moreover, the proposed oscillator based on SISL technology has the advantages of low cost, compact size, and self-packaging properties.

A High-Efficiency SISL-Based Slot Antenna Array for Wireless Power Transmission Application

A high-efficiency slot antenna array based on substrate integrated suspended line (SISL) technology operating at 24 GHz is presented for wireless power transmission (WPT) application. Because of the feature of self-shielding and low loss of SISL technology, double-side SISL (DSISL) is used to further reduce substrate and conductor loss in antenna design. Besides, four radiating slots are etched on the top ground layer of DSISL and serially fed as a subarray without any extra feeding network. By utilizing DSISL and avoiding network loss, a high efficiency subarray is realized with simulated efficiency of up to 89% at 24 GHz. In addition, the subarray is fabricated and measured. The measured results of subarray show that the 10 dB impedance bandwidth is from 23.75 to 24.1 GHz, which covers the WPT band (24 GHz ± 100 MHz). The measured gain of 13.1 dBi and radiation efficiency of 83.5% is achieved at 24 GHz. Besides, the width of air cavities can be further reduced to 0.384λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> (λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the free space wavelength at 24 GHz), benefiting from the basic mode tangential electromagnetic (TEM) mode of DSISL, which is good for wide scanning phased array design. Based on the subarray, a 1×8 phased array is designed and fabricated. The measured results show that |S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> | of −32 dB, isolation of 19 dB, and gain of 19.5 dBi is obtained at 24 GHz, while a wide scanning range of ±50°with gain drop less than 3.3 dB is achieved also at 24 GHz.

A wideband transition from substrate integrated suspended parallel strip line (SISPSL) to differential shielded GCPW

AbstractIn this paper, a novel wideband substrate integrated suspended parallel strip line (SISPSL) to differential shielded grounded coplanar waveguide (GCPW) transition is proposed. By embedding the traditional double‐side parallel‐strip line inside multilayer boards, SISPSL has the advantage of self‐packaging and there is almost no radiation loss. SISPSL has inherent differential transmission properties, and a transition from SISPSL to differential GCPW is designed based on multilayer boards. The measured bandwidth of the back‐to‐back transition is from 0.01 to 40 GHz.

Hybrid Integration of Chips Using SISL for Ka-Band High Combining Efficiency Power Amplifier

Hybrid integration of millimeter-wave (mm-wave) chips for power combining amplifier using substrate-integrated suspended line (SISL) is studied for the first time in this letter. A bond wire compensation structure with small size, wide bandwidth, and cavity mode suppression is proposed, and the wire bonding interconnect obtains the bandwidth of 0–48 GHz. A power combining amplifier based on this structure is proposed and the heat dissipation optimization is carried out. Finally, a four-way full Ka-band spatial power combining amplifier with high combining efficiency is fabricated. From 26 to 40 GHz, the maximum output power at the 1-dB compression point is 31 dBm, and the power combining efficiency is 78%–93%.

A Differential SISPSL Branch-Line Coupler With Common-Mode Suppression Using Compensated Stub

In this brief, a novel differential branch-line coupler based on substrate integrated suspended parallel strip Line (SISPSL) is proposed. The differential branch-line coupler is based on the multilayer structure, and utilizes the inherent differential characteristics of parallel strip line to construct the feeding port. The common-mode suppression is enhanced by loading a quarter-wavelength stub on the main transmission line at each port. The proposed SISPSL coupler is designed and fabricated using the PCB process, and it has the advantages of self-packaging and high common-mode suppression.

A Self-Packaged SISL Low-Power Rectifier Based on a High-Impedance Line for C-Band Applications

In this letter, a self-packaged substrate-integrated suspended line (SISL) rectifier is proposed. The rectifier consists of a quarter-wavelength high-impedance transmission line, a diode, a tuning inductor, and a dc pass filter. The lower the power is, the lower the rectifying efficiency is. At a low input power level, the diode impedance real part is almost zero. A tuning inductor is introduced to form a parallel resonator to enhance the diode voltage. A quarter-wavelength high-impedance line is presented to match the rectifying diode to the source. In addition, due to the self-packaging characteristics and air cavity of SISLs, the radiation loss and dielectric loss of the proposed rectifier are reduced. A rectifier was designed, fabricated, and measured at 5.8 GHz. The radio frequency (RF)-dc conversion efficiency reaches 3.5% at −30 dBm, which is close to its theoretical estimated efficiency at 5.8 GHz. This ultralow power rectifier may be used in energy harvesting at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C$ </tex-math></inline-formula> -band.

Broadband flip‐suspended‐microstrip transition for millimeter‐wave MMIC package

AbstractIn this letter, a novel millimeter‐wave chip packaging method based on flip‐suspended‐microstrip technology is proposed. The flip‐suspended‐microstrip contains a waveguide probe, a suspended microstrip line, input and output matching lines, and a terminal pad. The waveguide probe realizes energy coupling from the rectangular waveguide, and the terminal pad above the signal pad of chip achieves power transmission via electronic contact. Thus, the bonding wires which will bring parasitic inductance at high frequencies are avoided. To validate the proposed packaging method, back‐to‐back modules with coplanar waveguide/low noise amplifier were fabricated. The measured insertion loss of the back‐to‐back transition with a 1.75‐mm‐long coplanar waveguide is 2.6–4.2 dB over the entire D‐band, while the packaging loss of the low noise amplifier module with the back‐to‐back transition is less than 2.2 dB at 120–170 GHz, which indicate that the proposed broadband transition is feasible for millimeter‐wave chip packaging.

A compact low‐pass filter using a miniaturized capacitor and honeycomb cavity on substrate integrated suspended line platform

AbstractThis article proposes a compact low‐pass filter (LPF) using a miniaturized capacitor, and honeycomb cavity based on the substrate integrated suspended line platform. A new method for miniaturizing capacitors is proposed, and simultaneously honeycomb cavities are adopted to extend the stopband. As a design case, a seven‐order quasi‐lumped‐element LPF with a cutoff frequency of 0.6 GHz is designed, fabricated, and tested. The size of the LPF is 0.085λg × 0.015λg × 0.012λg, and a wide stopband from 0.82 to 67 GHz with a suppression level greater than 20 dB is obtained.

BUILDING DATABASE IN BALANCING KNITTED GARMENT LINES SOFTWARE IN INDUSTRY

The garment industry is one of the key industries contributing to the economic growth of Vietnam. Industry 4.0 has significantly altered the operational procedures of conventional enterprises. The implementation of technological, digital, and artificial intelligence applications has increased the global efficacy of corporate governance. To successfully assimilate into the regional and global economies, Vietnamese businesses must enhance their management capabilities and maximize both the quantity and quality of their products. In order to achieve this objective, the authors have conducted research to develop a database of sewing line balancing implemented in Assembly Line Balancing software for two common knitted products, namely Polo- Shirts, and T-Shirts. School of Textile-Leather and Fashion, Hanoi University of Science and Technology (HUST) methods compared and evaluated this result of sewing line balancing of 2 Polo-Shirt and T-Shirt products according to the manual, software, and actual calculation method at 3 enterprises: Star Fashion Company Ltd., Regent Garment Factory Ltd., and Hanoi General Textile Garment Joint Stock Company (Hanosimex). Since then, we have completed the sewing line balancing database for Polo-Shirt and T-Shirt products to row sewing lines for cases in which the path of semi-finished products is both straight and zigzag. The findings of this study can be applied to group conjugation lines and suspended lines transporting semifinished goods. The database has been constructed meticulously and standardized to ensure the diversity, richness, and universality of all product technology structure options applicable to garment companies. The database is utilized in the Assembly Line Balancing software developed by the research team; this is an application-oriented research product that will transfer technology to garment enterprises producing knitwear, assisting them in overcoming current challenges. Reasonable production line layout contributes to optimizing existing production conditions, increasing labor productivity and the efficiency of production organization, and laying the groundwork for the application of digital technology.

Wideband Millimeter-Wave Substrate Integrated Suspended Twisted Line for High-Speed Transmission

This paper proposes a novel substrate integrated suspended twisted line (SISTL), which can broaden the transmission bandwidth of the transmitted signal and reduce the external radiation of the transmission line through a self-packaging format. Specifically, the wide transmission bandwidth is obtained in this designed structure by combining theoretical analysis and optimizing the variables. The mixed-mode scattering parameters and eye diagrams are employed to measure the quality of the transmitted signal, demonstrating the feasibility of the proposed design. Moreover, the results show that the max bandwidth of SISTL is more than 50 GHz, and at this time, the data transmission rate can be up to 32 Gbps with an exemplary eye diagram and a low bite error rate.

A Low-Cost Miniaturized Filtering Dielectric Resonator Antenna Based on SISL for 5G Applications

To realize a low-cost, miniaturized, and high selective design, the filtering dielectric resonator antenna (FDRA) for 5G applications is first proposed based on the substrate-integrated suspended line (SISL). The FDRA consists of two same rectangular DRs embedded in air cavities, which are fixed by the hollowed substrate rings. A T-shape feeder, rectangular feeder, and metalized holes are introduced to excite the fundamental <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm {TE}}_{\delta 11}^{x}$ </tex-math></inline-formula> mode of DRA. The substrate rings and DR are regarded as a composite dielectric to miniaturize the antenna and have effects on the radiation nulls. Because of the different loading effects from the different feeders, the resonance frequency of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm {TE}}_{\delta 11}^{x}$ </tex-math></inline-formula> mode excited by the different feeders is slightly different. Therefore, a wide bandwidth can be achieved. In the hybrid feed scheme, three radiation nulls are introduced near the edge of the frequency band without an extra filtering circuit. To improve the suppression level, the effective size of the radiator is increased by increasing the width of the substrate rings without changing the size of the whole structure. Therefore, two prototype antennas with different widths of substrate rings are designed, manufactured, and measured. Good agreement can be observed between simulated and measured results.

A Low-Cost SISL Differentially Fed Dual-Polarized Stacked Patch Antenna With Enhanced Common-Mode Suppression Using Characteristic Mode Analysis

A wideband differentially fed dual-polarized stacked patch antenna with high common-mode (CM) suppression is proposed in this article using the characteristic mode analysis (CMA) and the substrate integrated suspended line (SISL) technology. Based on the CMA, orthogonal slots are loaded within the stacked patch to enhance the directivity of the second-order degenerate modes and reallocate the resonating frequency of the fundamental degenerate modes. A crossed dipole is introduced within the driven patch to ensure polarization uniformity between the two paired degeneracies. The CM suppression level ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{S}_{\mathrm {CC}}11$ </tex-math></inline-formula> ) is enhanced from–10 to–1.30 dB within the frequency range of 4.0–7.0 GHz by embedding circular slots embedded within the stacked patch and controlling the slot radius. Measured results demonstrate a–10 dB differential impedance bandwidth of 28.4% (4.62–6.18 GHz) and high isolation of better than–39.5 dB between the differential ports. The antenna depicts stable measured radiation patterns with low cross-polarization (<–30 dB). The measured average antenna gain and efficiency are 9.55 dBi and 85.5% within the DM passband. In addition, a high <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{S}_{\mathrm {CC}}11$ </tex-math></inline-formula> better than–1.05 dB is measured within the desired DM band.

Direct laser writing breaking diffraction barrier based on two-focus parallel peripheral-photoinhibition lithography

Direct laser writing (DLW) enables arbitrary three-dimensional nanofabrication. However, the diffraction limit poses a major obstacle for realizing nanometer-scale features. Furthermore, it is challenging to improve the fabrication efficiency using the currently prevalent single-focal-spot systems, which cannot perform high-throughput lithography. To overcome these challenges, a parallel peripheral-photoinhibition lithography system with a sub-40-nm two-dimensional feature size and a sub-20-nm suspended line width was developed in our study, based on two-photon polymerization DLW. The lithography efficiency of the developed system is twice that of conventional systems for both uniform and complex structures. The proposed system facilitates the realization of portable DLW with a higher resolution and throughput.

An active‐passive cascaded bandpass filter with an 88 kHz–1.1 GHz bandwidth on substrate‐integrated suspended line platform

AbstractThis letter proposes an active‐passive cascaded bandpass filter based on the substrate‐integrated suspended line platform for the first time. By cascading an active‐RC highpass circuit with a passive‐LC lowpass filter circuit, the proposed filter achieves a GHz bandwidth, an extremely low cut‐off frequency, and a controllable in‐band gain. It has the advantages of compact size, DC‐offset cancellation, and self‐packaging. As proof of concept, a sixth‐order bandpass filter was designed and fabricated. The measured 3‐dB bandwidth is from 88 kHz to 1.1 GHz with a 5.8 dB in‐band gain, and the circuit area is only 0.021 × 0.022 λg, where λg is the guided wavelength at 0.55 GHz.

A 3 dB SISL coupler design by multi‐objective evolutionary algorithm based on decomposition

In this article, a 3 dB substrate integrated suspended line (SISL) coupler design by multi-objective evolutionary algorithm based on decomposition (MOEA/D) is proposed. SISL technology can provide electromagnetic shielding performance and realize the low loss, lightweight, and self-packaging. The highly time-consuming problem of adopting traditional electromagnetic (EM) simulation software to assist coupler design is always the main problem for the design of couplers. To solve the problem, this article applies MOEA/D based on one-dimensional convolutional autoencoders (1D-CAE) to assist coupler design. 1D-CAE model builds the surrogate model to help MOEA/D find out better responses faster. MOEA/D has some advantages of saving time and getting good performance easily.

A sequentially rotated feeding circularly polarized stacked patch antenna array based on SISL

AbstractA sequentially rotated feeding circularly polarized stacked patch antenna and its array based on substrate integrated suspended line (SISL) are presented. The resonant frequencies of 5.05 and 5.35 GHz are obtained by using the cross slot on the driven patch, which can also realize circular polarization. The windmill stacked patch is introduced to generate another resonant frequency of 5.85 GHz and expand 3‐dB axial ratio (AR) bandwidth (BW). The measured 10‐dB impedance BW of 18.2% (4.98–5.98 GHz) and the 3‐dB AR BW of 3.6% (5.45–5.65 GHz) are obtained from the proposed antenna element. The measured peak gain is 9.0 dBi. A sequentially rotated feeding is used to excite the proposed 2 × 2 antenna array. The measured peak gain is 13.31 dBi. The measured 10‐dB impedance BW is 28.3% (4.80–6.38 GHz) and the 3‐dB AR BW is 8.9% (5.35–5.85 GHz).

FR‐4‐based Ka‐band SISL bandpass filters using folded half‐wavelength resonators

AbstractIn this letter, bandpass filters (BPFs) with folded short‐circuited half‐wavelength (λ/2) resonators are proposed based on the substrate integrated suspended line (SISL) platform for satellite communications. Each λ/2 resonator is folded, to achieve an overlapping structure, which not only reduces the size, but more importantly, reduces the loss. In addition, air cavity, metal shielding wall, and substrate excavation method also dramatically reduce the loss in substrates. Note that professional material term (FR‐4) material is chosen for the design, therefore, it is low‐cost and more suitable for production application. Finally, a second‐order and a fourth‐order combline BPFs are fabricated and measured to verify the design method. The insertion loss of the second‐order and the fourth‐order filters are only 0.78 and 1.19 dB at the center frequency of 29.2 GHz, respectively. The presented SISL filters using FR‐4 material demonstrate the advantages of low‐loss, low‐cost, and self‐packaging.

Young Women and Disgust in Contemporary Norwegian Comics: A Close Reading of Ane Barstad Solvang's Frykt &amp; medlidenhet

Young Women and Disgust in Contemporary Norwegian Comics: A Close Reading of Ane Barstad Solvang's <i>Frykt</i> &amp; <i>medlidenhet</i>

An SISL-Based 24-GHz FMCW Radar With Self-Packaged Six-Port Butler Matrix Receiver

A 24-GHz frequency modulated continuous wave (FMCW) radar system with self-packaged six-port Butler matrix receiver using substrate integrated suspended line (SISL) platform is proposed in this article. Since all active and passive components are integrated on the SISL platform using the standard printed circuit board (PCB) process, the proposed system is highly integrated with low cost. The system is composed of a transmitting (TX) antenna, a Butler matrix with a receiving (RX) antenna array, a single pole four throw (SP4T) switch, a low noise amplifier (LNA), and a six-port receiver. The Butler matrix and SP4T switch are implemented for beam scanning, which has the advantages of low loss and compact size. The SISL-based six-port receiver is designed for quadrature downconversion. The supporting digital signal processing algorithms are also proposed for the calculation and display of multiple targets information. The radar system has shown excellent performance in the measurement of indoor environment, including range, velocity, and direction of arrival (DOA). The proposed radar provides a new solution for a transceiver system.

Thermal resistance mapping along a single cup-stacked carbon nanotube with focused electron beam heating

The structural non-uniformity in low-dimensional materials, including interfaces and defects, makes it highly desirable to map the thermal property distribution with a high spatial resolution. Meanwhile, eliminating the error of thermal contact resistance at the sample-sensor junction has remained a critical challenge in nanoscale thermal conductivity measurement. Here, we combine the electron beam (EB) heating with two suspended line-shaped heat flux sensors and have achieved the in-situ thermal resistance mapping along a single cup-stacked carbon nanotube (CNT) in a scanning electron microscope (SEM). The CNT is anchored between the two suspended metal lines, and the focused electron beam heats the CNT locally with a nanometer-range spatial resolution, while the two metal lines simultaneously measure the heat fluxes induced by the EB heating. By sweeping the focused EB along the CNT, we can obtain the spatially resolved thermal resistance, from which the true thermal conductivity of the CNT was extracted to be around 40 W/m·K without the thermal contact resistance error. This SEM-based in-situ thermal measurement method can accelerate high-resolution nanomaterials characterization and the elucidation of nanoscale heat transfer.