Single Printed Circuit Board Research Articles

Ultra-Wideband Phased Array for Millimeter-Wave ISM and 5G Bands, Realized in PCB

In this paper, we present the design, fabrication, and measurement of an ultra-wideband phased array antenna, with continuous coverage of all six allocated fifth generation and industrial, scientific, medical bands in the millimeter-wave spectrum. Of importance is that the complete array is co-fabricated as a single printed circuit board using commercial processes, implying a significant reduction in cost over previous microfabrication-based designs. The design is demonstrated in simulation to operate across 24–72 GHz with VSWR $3\times 3$ array prototype, which shows close agreement to the simulated values.

A 60-GHz Transceiver and Baseband With Polarization MIMO in 28-nm CMOS

Polarization (pol) selectivity has been widely adopted in modern RF transceivers to enable the channel diversity. This paper utilizes orthogonal pol modes to support simultaneous independent data streams on the same frequency channel, thereby doubling the effective channel capacity. The energy-efficient 60-GHz transceiver prototype uses two transmit/receive (TX/RX) chains with a single printed circuit board (PCB) antenna to demonstrate over-the-air (OTA) 2 × 13.9 Gb/s 16 quadrature-amplitude modulation (QAM) dual-pol (DP) multiplexing-based multi-input and multi-output (MIMO), thus achieving 2× higher communicated bits/symbol than a single-pol transceiver. At these multi-Gb/s rates, multi-path ISI and cross-pol effects limit the feasibility of DP-MIMO. To mitigate these channel effects, a mixed-signal 384-coefficient feed-forward equalizer (FFE)- and 2400-coefficient decision-feedback equalizer (DFE)-based areaand energy-efficient RX baseband is also presented. The baseband supports DP-MIMO up to 40 Gb/s for line-of-sight (LOS) 16QAM and 14 Gb/s non-line-of-sight (NLOS) QPSK, at 3× to 38× better energy efficiency per coefficient than state of the art.

EM design and analysis of a substrate integrated waveguide based on a frequency-selective surface for millimeter wave radar application

Substrate integrated waveguide (SIW) technology makes it possible to realize an entire circuit including a transition, planar circuitry, waveguide components and devices in a single printed circuit board. In this paper, a new approach to design a substrate integrated waveguide using a single square loop and Jerusalem cross frequency-selective surface elements as the top wall in place of a metallic wall, for advanced millimeter wave radar systems is presented. The guided wave and modes operating at the high-frequency range in V-band, typically 40–75 GHz (57–64 GHz in the USA and 59–66 GHz in Japan), has been analyzed. The accurate analytical modeling is used to calculate the complex propagation constant and cut-off frequency of the SIW structure. The propagation constant of the analyzed structured is compared with a conventional SIW, and the wave propagation is presented in all topologies. The leakage and attenuation loss of an electromagnetic wave due to different factors such as dielectric, conductor and radiation are also studied. Finally, the numerical simulation has been performed based on finite element and finite difference time domain to prove the analytical formulation of the proposed structure. The obtained simulation results are encouraging for developing a new type of SIW structure for aerospace applications.

63.5–65.5-GHz Transmit/Receive Phased-Array Communication Link With 0.5–2 Gb/s at 100–800 m and ± 50° Scan Angles

This paper presents a 32-element phased array centered at 64 GHz using multiple SiGe chips on a single printed-circuit board. The antenna element is a series-fed patch array, which provides directivity in the elevation plane. The transmit array results in an effective isotropic radiated power of 42± 2 dBm at 63–65.5 GHz, while the receive array provides an electronic gain of 24 dB and a system noise figure <7.7 dB, including antenna loss, T/R switch, beamformer, and transceiver. The arrays can be scanned to ±50° in the azimuth using a 5-bit phase shifter on the SiGe chip without degradation in sidelobes and maintaining a near-ideal pattern. A communication link between two phased arrays at 100, 300, and 800 m is also demonstrated, and employs one array on the transmit side and another array on the receive side, together with external mixers and IF amplifiers. The link performance was measured for different scan angles and modulation formats. Data rates of 0.5–2 Gb/s using 16-QAM and QPSK waveforms are demonstrated at 100–800 m, with 2-Gb/s data rate at 300 m and ~500-Mb/s data rate at 800 m. To the best of our knowledge, this is the first system-level demonstration of a silicon-based Gb/s 60-GHz phased array over hundreds of meters. Application areas are in point-to-multipoint links, back-haul and front-haul links, and reconfigurable mesh networks for advanced communication systems.

Nanotransducers on printed circuit boards by rational design of high-density, long, thin and untapered ZnO nanowires

Nanotransducers can offer crucial advantages in comparison with conventional sensors and actuators. However, interfacing and packaging nanostructures into complete electronic systems is very complex. Here we describe a wet chemical method for cointegrating arrays of ZnO nanowires into systems on printed circuit boards (PCBs). First, we deposit on the PCB a MnOOH layer for reproducibly increasing the nanowires density. Afterwards, we numerically demonstrate that the ligand ethylenediamine, at the isoelectric point of the ZnO nanowires tips, can effectively control, at very low concentrations, both zinc speciation and supersaturation in the nutrient solution. Accordingly, we combine potassium chloride and ethylenediamine, produced in situ from a safer precursor (ethanolamine), for concurrently thinning the nanowires (top width around 60nm) and stabilizing their top faces. Our synergic approach enables the solution growth of ZnO nanowires which are untapered and have high densities (> 8/μm2) and record length (> 15µm) and aspect ratio (> 200) for plastic substrates which may not withstand high temperatures. These characteristics permit to simultaneously add the top electrode, package the nanowires, improve their mechanical robustness and connect to the electronic interface by a simple flip chip adhesive bonding procedure. As proofs of concept we describe flexible PCB heaters (electrical to thermal energy conversion) with power densities comparable with state of the art flexible heaters and a wearable piezotronic heartbeat detector comprising both ZnO nanowires (mechanical to electric energy conversion) and electronics on a single flexible PCB. Our results open the way to the cointegration of nanotransducers and electronics on conventional PCBs.

Low-Cost Wideband mm-Wave Phased Array Using the Piezoelectric Transducer for 5G Applications

This paper presents a 55–65 GHz 16-element beam-steering array with a low-cost piezoelectric transducer-controlled phase shifter employing a single printed circuit board substrate. An ultrawideband antipodal fermi tapered slot antenna element with sine corrugation is designed to achieve symmetric E- and H-plane radiation patterns. The array is fed with an amplitude taper wideband Y-junction power divider integrated with an electromagnetic bandgap structure surrounding the feeding network. The measured results show a wide impedance bandwidth of S11 < −10 dB covering the band 55–65 GHz. The array measured gain is around 20 dB with low radiation losses. The 60-GHz phased array’s wide BW coverage, high gain, low feeding network loss, low cost, and low profile should have wide applications in the development of ultrawideband millimeter-wave scanning systems for the fifth generation communication applications.

PCB Fault Detection Using Image Processing

The importance of the Printed Circuit Board inspection process has been magnified by requirements of the modern manufacturing environment where delivery of 100% defect free PCBs is the expectation. To meet such expectations, identifying various defects and their types becomes the first step. In this PCB inspection system the inspection algorithm mainly focuses on the defect detection using the natural images. Many practical issues like tilt of the images, bad light conditions, height at which images are taken etc. are to be considered to ensure good quality of the image which can then be used for defect detection. Printed circuit board (PCB) fabrication is a multidisciplinary process, and etching is the most critical part in the PCB manufacturing process. The main objective of Etching process is to remove the exposed unwanted copper other than the required circuit pattern. In order to minimize scrap caused by the wrongly etched PCB panel, inspection has to be done in early stage. However, all of the inspections are done after the etching process where any defective PCB found is no longer useful and is simply thrown away. Since etching process costs 0% of the entire PCB fabrication, it is uneconomical to simply discard the defective PCBs. In this paper a method to identify the defects in natural PCB images and associated practical issues are addressed using Software tools and some of the major types of single layer PCB defects are Pattern Cut, Pin hole, Pattern Short, Nick etc., Therefore the defects should be identified before the etching process so that the PCB would be reprocessed. In the present approach expected to improve the efficiency of the system in detecting the defects even in low quality images

A Novel Six-Axis Force/Torque Sensor for Robotic Applications

This paper presents a novel six-axis force/torque (F/T) sensor for robotic applications that is self-contained, rugged, and inexpensive. Six capacitive sensor cells are adopted to detect three normal and three shear forces. Six sensor cell readings are converted to F/T information via calibrations and transformation. To simplify the manufacturing processes, a sensor design with parallel and orthogonal arrangements of sensing cells is proposed, which achieves the large improvement of the sensitivity. Also, the signal processing is realized with a single printed circuit board and a ground plate, and thus, we make it possible to build a lightweight six-axis F/T sensor with simple manufacturing processes at extremely low cost. The sensor is manufactured and its performances are validated by comparing them with a commercial six-axis F/T sensor.

Application of the model of the printed circuit board with regard to the topology of external conductive layers for calculation of the thermal conditions of the printed circuit board

The paper proves the necessity of taking into account external conductive layers of the printed circuit board with the thermal physical designing radio-electronic means. For example, a single printed circuit board shows the level of influence of the external conductive layer on the thermal conditions of the printed circuit board. It proved the influence of Joule heat in the thermal conditions of a single conductor. Developed geometrical and thermal printed circuit board models take into account the topological layer and can improve the accuracy of determining the thermal conditions of the printed circuit board.

A low-cost design experience for junior-level electronics circuits laboratories through emulation of industry-printed circuit board design practice

Over a 2-year period, printed circuit board layout design and test were included in the laboratory portion of the second of two junior-level electronic circuits courses. Printed circuit board design using industry-accepted board specifications and standard industry Gerber file export experience was developed. The students’ printed circuit board design experience emulated real-world situations and cost criteria. The instructor served as the fabricator in this model of the industrial design situation. Students individually used industry standard schematic capture and layout software to develop a printed circuit board for a simplified discrete µA741 operational amplifier. The layout designs were submitted as industry standard Gerber files electronically to the instructor/fabricator for evaluation. Grades were assigned by evaluating the accuracy and cost effectiveness of the design by minimizing traces, reducing printed circuit board geometry, and limiting the number of vias, which ultimately reduces fabricator tooling cost. Feedback was provided by the instructor who acted as the industry fabricator to individual students. A single fabricated printed circuit board, designed by the instructor (and fabricated by a commercial printed circuit board manufacturer), was delivered to students for assembly and test. By delivering a single printed circuit board design to students, fabrication costs can be minimized and students can inspect the delivered board as an exemplar. Assessments of the student perceptions of knowledge of and confidence in applying printed circuit board techniques in designing and releasing a printed circuit board were conducted prior to and after the printed circuit board layout design and test. On a 5-point scale, overall student-reported knowledge increased by 2.14 and overall student confidence increased by 1.20 points. Faculty assessment of knowledge, as measured by scoring short answers to knowledge statements, correlated well with student report and showed an average increase of 2.70.

A Capacitive-Type Novel Six-Axis Force/Torque Sensor for Robotic Applications

This paper presents an innovative design of a six-axis force/torque sensor, which enables ease of manufacturing, cost reduction, and ruggedness in operation. The advantages are realized by simplifying the structure of the sensor and reducing manual labor during the manufacturing process. In order to achieve a simple sensor structure, we propose a capacitive-type force sensing scheme in which the sensing elements are aligned in-plane. By using this method, all the sensing elements can be fabricated on single printed circuit board, and thus, manual tasks, such as bonding and coating the sensing elements, can be eliminated. In order to verify the feasibility of the idea, a prototype six-axis force/torque sensor was manufactured, and its performances were evaluated. The characteristics of the prototype are analyzed in terms of condition number, static response, time domain response, hysteresis, repeatability, and time drift.

Wideband, Wide-Scan Planar Array of Connected Slots Loaded With Artificial Dielectric Superstrates

Microwave broadband wide-scan antenna arrays are typically implemented resorting to vertical arrangements of printed circuit boards (PCBs). Here, we propose a planar solution realized with a single multi-layer PCB, with consequent reduction in cost and complexity of the array. It consists of an array of connected slots backed by a metallic reflector and loaded with superstrates. Artificial dielectric layers (ADLs) are used in place of real dielectrics to realize the superstrates, as they are characterized by very low surface-wave losses. For the unit-cell design, we developed an analysis tool based on closed-form expressions and thus requiring minimal computational resources. Finite-array simulations are also performed by generalizing the analysis method to account for the truncation effects. The presence of the ADL superstrate allows reducing the distance between the array plane and the backing reflector while maintaining good matching performance. A realistic feed structure is also proposed, which consists of a microstrip line connected to a coaxial feed. Such a solution does not require balanced-to-unbalanced transitions, which often limit the achievable bandwidth. The proposed structure achieves in simulations more than an octave bandwidth (6.5–14.5 GHz), within a scanning range of $\pm 50$ ° in all azimuth planes.

A low-cost UWB sensor node powered by a piezoelectric harvester or solar cells

We propose an autonomous battery-less wireless sensor node that combines on a single printed circuit board an ultra-wideband (UWB) transmitter and its printed antenna, together with a piezoelectric cantilever and a solar cell array to harvest vibrations and light energy, respectively. The co-design of the solar cell array with the printed UWB antenna allows a prototype size of only 85×35mm2, i.e., less than 65% of a credit card size. Low-cost is achieved by using inexpensive FR4 dual-layer substrate, standard-ceramic capacitors, and low-cost harvesters. The vibrational energy scavenger is fabricated at the wafer scale based on commercially available bulk polycrystalline Lead Zirconate Titanate (PZT), and the solar cells are fabricated by depositing amorphous-Si on 0.5mm thick glass substrate. The cold-startup time of the demonstrator is about 42min under indoor-ambient light conditions, and about 34min under 700mg vibrations at a frequency of 100Hz. Once started, the sensor requires only 12.6μW to allow a transmission rate of one temperature sensor readout every 34s, thanks to the UWB transmitter that consumes only 206 pJ per pulse and a custom protocol with a reduced overhead.

Analysis of Compact Triple-Mode Ceramic Cavity Filters Using Parallel-Coupled Resonators Approach

A design and analysis approach that enables extracting the full filtering potential of triple-mode filters while greatly simplifying the construction and hence reducing the filter cost is presented. The presented way views multimode resonators of cavity filters as resonators coupled in parallel, with every mode within the structure completely orthogonal; hence, there are no interresonator couplings. Each resonator then independently sees the interfacing input and output while the strength and phase of the coupling, along with the resonator frequencies, dictate the transmission zero placement. Thus, a completely general frequency response can be attained with as many arbitrarily placed zeros as there are multimode resonators. The absence of intracavity couplings allows using a simple rectangular cuboid while the input-to-output coupling via a single printed circuit board interface manages three controllable transmission zeros per cuboid. To verify the proposed approach, multiple designs operating at the DCS-1800 Band-3 are presented.

Tri-axis magnetometer with in-plane giant magnetoresistance sensors for compass application

A tri-axis magnetometer comprising three giant-magnetoresistance sensors and a cylindrical fluxguide are implemented for compass application. The sensors are mounted on a single printed circuit board (PCB) board with their sensing axes in a plane. A calibration process involving matrix manipulation was employed to make the device function as a tri-axis magnetometer with orthogonal sensing directions. The capability of the device for compass application was demonstrated by measuring its azimuth response to the geomagnetic field about different rotation axes. The proposed calibration technique can be used for the magnetometer system with either orthogonal or non-orthogonal sensor arrangement.

Circularly Polarized Triband Printed Quasi-Yagi Antenna for Millimeter-Wave Applications

This paper describes the design and development of a triband with circularly polarized quasi-Yagi antenna for ka-band and short range wireless communications applications. The proposed antenna consists of an integrated balun-fed printed dipole, parasitic folded dipole and a short strip, and a modified ground plane. The antenna structure, together with the parasitic elements, is designed to achieve circular polarization and triband operating at resonant frequencies of 13.5 GHz, 30 GHz, and 60 GHz. Antenna design was first simulated using HFSS ver.14, and the obtained results were compared with experimental measurements on a prototype developed on a single printed circuit board. Achieved characteristics include −10 dB impedance bandwidth at the desired bands, circular polarization axial ratioAR&lt;3 dB, front to back ratio of 6 dB, gain value of about 4 dBi, and average radiation efficiency of 60%. The paper includes comparison between simulation and experimental results.

Printed Circuit Board Fault Inspection Based on Eddy Current Testing Using Planar Coil Sensor

This paper presents a printed circuit board (PCB) fault inspection method using eddy current testing generated from Helmholtz coils with a planar array-coil sensor to locate and inspect short and open faults on uniformly spaced interconnect single layer PCBs. The differences between the induced voltages from fault-free boards and faulty boards will be recorded in tables and translated into contour plots. The experimental results showed that in the presence of a short fault, the differences between the induced voltages from fault-free and faulty boards are highly negative. However, in the presence of an open fault, the differences between the induced voltages from fault free and faulty boards are highly positive. These highly positive or negative induced voltages can be translated into high density color regions on contour plots. The potential fault positions can be located by observing the color regions of the contour plots with respect to each element of the matrix sensor.

FPGA based flexible UWB pulse transmitter using EM subtraction

An all-digital field programmable gate array based electromagnetic subtraction technique for direct UWB pulse generation is presented. Using this technique, it is possible to generate Gaussian pulses, monocycles or doublets with high flexibility using a single printed circuit board layout. User-controlled parameters include amplitude, pulse-width, pulse-type, repetition rate or even modulation. Measurements indicate a Gaussian pulse with 1.24 V peak amplitude and a 10% pulse-width of 670 ps can be transmitted at a repetition frequency of 100 MHz. The corresponding − 10 dB bandwidth is 2.8 GHz.

SmartGate – connecting wireless sensor nodes to the Internet

Abstract. Wireless sensor nodes inside buildings are used to read out sensor data and to control actuators. The nodes need to operate for a long time with a single battery. Often the sensor data should be accessible via Internet from every point of the world. When using a standard Wi-Fi connection, the battery of the node would be depleted after a few hours due to idle currents in receive state. Using sensor nodes with included wake-up receivers can prolong the lifetime of the sensor network to several years. However, no gateway exists that can, on the one hand, connect itself to the Internet and on the other hand can send out the special coded wake-up signal needed by the wake-up receivers on the nodes. In this work we want to bridge this gap by introducing the SmartGate. It is a gateway that has two transceivers incorporated on a single printed circuit board (PCB). A Wi-Fi module connects itself to an existing Wi-Fi network and listens for incoming messages. A CC430 microcontroller analyzes the incoming Wi-Fi messages and builds up the corresponding wake-up signal with included 16-bit address coding. The wake-up signal is sent out using the integrated CC1101 transceiver core from Texas Instruments. A woken-up node will read out its sensor data and will transmit it back to the gateway, where it will be packed into a TCP/IP packet and sent back to the user. The use of the gateway allows the implementation of a wireless sensor network with wake-up receivers that can be accessed via Internet from every point of the world.

A magnetic induction measurement system for adult vital sign monitoring: evaluation of capacitive and inductive effects

Magnetic induction (MI) measurement technique could provide an unobtrusive contactless method for continuous monitoring of vital signs such as breathing and cardiac activity in bed. In this paper, we present a magnetic induction system to evaluate the feasibility of monitoring heart and lung activity and the preliminary measurement results. The excitation and detection coils are designed to be implemented in a single printed circuit board, allowing the use of the system in a bed with coils under the mattress. The electronic system is based on a 16 bit arbitrary waveform generator (PXI-5422, National instrument) operating at a sample rate of 200 MS/s for the excitation signal and the detected amplified signal is then, sampled at 100 MS/s by a 14 bit digitizer (PXI-5122, National Instruments). The preliminary results at 10 MHz show the ability of the system to detect solutions with different conductivities. However the capacitive effect is in the same order of magnitude as the inductive effect due to eddy currents. Safety of the system has been evaluated to be in accordance with the standards of human exposure to the magnetic fields.