Single-layer Printed Circuit Board Research Articles

Design of Low-Cost Single-Layer 2-Bit Reflective Programmable Metasurface Based on Folded Ground

A low-cost single-layer 2-bit programmable metasurface (PM) is proposed in this article. This PM is processed on a single-layer printed circuit board (PCB) with the microwave structure, ground, and bias lines, enabled by a folded ground. The folded ground design moves a part of the ground from the bottom to the top layer to leave an area for bias lines. Vias are used to connect the ground in top and bottom layers to form a whole. The bias line in the microwave structure area is grounded by two capacitances to isolate microwave current with the bias line area. An asymmetric patch is designed in microwave area as the 2-bit microwave structure. To verify the microwave performance of this PM, functions of generating double beams, electromagnetic (EM) waves with orbital angular momentum (OAM), and a high gain beam are simulated. The far-field pattern of a 16 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times$</tex-math> </inline-formula> 16 PM antenna in beam scanning is measured. The measured results show that the PM antenna has a beam scanning capability of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\pm$</tex-math> </inline-formula> 60 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> and a maximum aperture efficiency of 44.6%. Finally, to illustrate the universality of the folded ground design, the varactor-loaded continuous phase adjustable PM and variable polarization 1-bit PM are discussed.

Design of High-Gain Single-Layer Endfire Antenna Using Phase-Reversed Asymmetric Spoof Surface Plasmon Polaritons

We present a novel endfire antenna based on asymmetric spoof surface plasmon polaritons (SSPPs) and phase-reversal technique. SSPPs structure allows it to be fabricated on a single-layer printed circuit board. Asymmetric SSPPs elements were employed to fulfill the condition of endfire radiation, and meanwhile, phase-reversal technique provides a high gain for the antenna. To verify the proposed design principle, a prototype was fabricated and measured. It exhibits a peak gain of 16.2 dBi within the operational frequency band of 17–19 GHz, featuring the highest endfire gain among all single-layer designs.

Compact or Wide-Stopband SIW Diplexers With High Intrinsic Isolations Based on Orthogonal Dual Modes

This brief proposes two miniaturized substrate integrated waveguide (SIW) diplexers with wide stopband and high isolation based on orthogonal dual-mode technique. With the orthogonal dual-mode SIW junction-resonators to eliminate the traditional T-junctions, significant circuit miniaturization and the inter-channel isolations can be achieved for SIW diplexers. Additionally, the fractional bandwidth (FBW) diagrams are utilized to identify the feasible FBWs in both passbands effortlessly. To verify the developed method, two types of SIW diplexers centered at 12 and 14 GHz are synthesized and fabricated utilizing a single layer printed circuit board technology. The performances of both diplexers are demonstrated by the measured and simulated results.

220 GHz High-Gain Substrate Integrated Antennas With Low Fabrication Cost Based on Higher Order Mode and PCB Technology

In millimeter-wave (MMW) and terahertz (THz) bands, the operation frequency is high and there are challenges in fabrication and microassembly processes, bringing high-accuracy requirements and high manufacturing cost. In this article, high-gain substrate integrated antennas with low fabrication cost are presented for MMW/THz applications. The basic antenna consists of two parallel TE201 resonant cavities and is directly fed by a grounded coplanar waveguide (GCPW). Radiation slot apertures are modified to increase aperture radiation efficiency and improve radiation patterns and gain. The antenna scheme is analyzed and a 220 GHz <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times2$ </tex-math></inline-formula> slot array antenna is developed as an example. To further improve the antenna gain with low fabrication cost and low feeding network loss, the basic antenna is explored to feed a modified dielectric plate lens. The high-gain scheme and design flowchart are provided. Both basic and improved structures are fabricated by normal single-layer printed circuit board (PCB) technology and high antenna gains are achieved. The measured peak gain of the basic antenna and the antenna with dielectric plate lens are 13.5 and 20.2 dBi, respectively. The measured return losses are better than 10 dB from 192 to 247 GHz. The antennas have advantages of simple antenna feeding structure, low fabrication cost, wide bandwidth, and high gain.

Synthesis of 3-D Polarization Rotation Transmissive Surface by Arbitrary Angle Based on Orthogonally Inserted Parallel-Couple Slotlines

In this article, a polarization rotation transmissive surface (PRTS) of arbitrary angle based on a three-dimensional (3-D) frequency selective structure is proposed. The PRTS unit cell is composed of three parallel-coupled slotline sections with open-short ends etched on vertically and horizontally inserted singlelayer printed circuit boards (PCBs). Under the incidence of vertically polarized waves, the spatial waves are converted into guided waves by the open-circuited end of one slotline section, and then the guided waves are coupled to two other slotline sections that can act as two independent coupling transmission paths in the orthogonal planes. This can be observed as a power divider, and the power division ratio can be fully controlled by virtue of the coupling strengths of the two coupling transmission paths. Thus, the polarization of incidence waves can be rotated at an arbitrary angle at the output port. To simplify the design procedure, a filtering power division theory and an equivalent circuit model are first used to obtain the theoretical response. Subsequently, a coupling matrix is employed to synthesize and design the proposed PRTS. To confirm the effectiveness of the proposed PRTS, two examples with different polarization rotation angles and fractional bandwidths at the same center frequency of 5 GHz and return loss of 20 dB are designed, fabricated, and measured. The measured results confirm our theoretical predictions and agree with the simulated results, thus demonstrating that the proposed PRTS exhibits stable frequency response under a large oblique incidence, in addition to their easiness in fabrication.

Synthesis of 3-D Polarization-Rotating Surface Based on Orthogonally Inserted Parallel-Coupled Slotlines

In this article, a second-order 3-D bandpass polarization-rotating surface (PRS) that can rotate vertically polarized incident waves by 90° and facilitate the output of horizontally polarized waves is presented. First, each PRS element is constructed using a pair of parallel-coupled slotline sections with open-short-ends, which are etched on vertically and horizontally inserted single-layer printed circuit boards (PCBs), respectively. Then, under vertically polarized incident waves, one of the slotline sections can convert the incident spatial waves into guided waves through its open end. After which, the guided waves are coupled to the other slotline section and the electric field direction will be rotated by 90° through the coupling path, thus leading to a 90° polarization rotation. Subsequently, a direct coupling matrix is used to synthesize and design the proposed PRS based on the microwave filter theory. Investigations reveal that a desirable bandpass filtering response can be obtained by properly designing the internal coupling of the parallel-coupled slotline sections and the external coupling between the incident spatial waves and the PRS. To validate the design concept, two examples with different fractional bandwidths at the same center frequency of 5 GHz and the same return loss of 20 dB were designed, fabricated, and measured. Consequently, a good agreement was attained among the results from coupling matrices, full-wave electromagnetic (EM) simulations, and measurements. All the results demonstrate that the proposed PRSs feature simple topologies, easy fabrications, low insertion losses (ILs), high polarization-rotating ratios, and stable filtering performances under large oblique incidences. In addition, our proposed method can be applied to design higher-order PRSs with sharpened out-of-band roll-off skirts.

Analysis and Design of a Stacked PCBs-Based Quasi-Helix Antenna

In this communication, a new class of circularly polarized (CP) antennas is presented. It is based on the utilization of stacked printed circuit boards (PCBs) in order to realize a quasi-helix. An end-cap disk is used to optimize the axial ratio (AR). Good impedance matching and low AR in a wide frequency band make the proposed antenna an excellent candidate for satellite communication systems and Wi-Fi applications. The structure is composed of eight PCB layers, where each layer is processed using regular single-layer PCB technology. The lowest PCB laminate is used for the feed network, while the higher stacked PCB laminates form the helical radiating element section. Seven microstrip 120° arcs are used on PCB laminates to form a quasi-helix structure, which, with the help of the end-cap disk, can generate electromagnetic CP radiation. A prototype of the proposed antenna for 5.8 GHz WLAN was fabricated and measured to validate the proposed concept. The measured operating bandwidth for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\vert S_{11}\vert &lt; -10$ </tex-math></inline-formula> dB is 33% (5.05–7.05 GHz). The measured 3 dB AR bandwidth covers a frequency band from 5.45 and 6.6 GHz (19.25%). Unidirectional radiation patterns with excellent performance in terms of CP and high front-to-back ratio were obtained over the operating bandwidth.

Miniaturized and Low Insertion Loss Diplexer Using Novel Inter-Digital Capacitors and Microstrip Section Inductors

A miniaturized and low insertion loss diplexer is proposed for Wifi applications (2.4 GHz-2.5 GHz and 5.15 GHz-5.85 GHz) in this brief. In each channel, the impedance transformations of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${K}$ </tex-math></inline-formula> -inverters and the couplings of lumped elements in the circuit are employed to create transmission zeros (TZs) in the stopband to ensure high selectivity and out-of-band rejection. Besides, the diplexer composed of two bandpass filters (BPFs) connected by T-junction achieves excellent impedance matching and high isolation. To alleviate difficulties of the design, the equivalent circuit is used for quantitative analysis. For a demonstration, the diplexer based on single-layer printed circuit board (PCB) technology using novel inter-digital capacitors and microstrip section inductors has been fabricated with a compact size of 14.6 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\times }\,\,10.48$ </tex-math></inline-formula> mm. The measured insertion losses are 1.67 dB for the first channel and 1.58 dB for the second channel, and the obtained isolation between the output channels is greater than 25.8 dB.

Wideband RWG-SIW Interconnection With Improved Integration for Millimeter-Wave/Terahertz Application

In this letter, wideband interconnections are proposed to connect metal rectangular waveguide (RWG) and substrate integrated waveguide (SIW) based on printed circuit board (PCB) technology. For the purpose of easy fabrications and micro-assembly processes in millimeter-wave/terahertz (MMW/THz) applications, a standard RWG is used to feed the transition without any manufactures in the metal waveguide. The wideband interconnection structure with improved impedance matching is only designed in a single-layer PCB. Particularly, the novel interconnections are realized by stepped dielectric transformers using PCB technology. These integrations have the advantages of simple structure, low fabrication cost, and easy processes. To demonstrate the scheme, two 220-GHz band interconnections are designed as examples. Back-to-back interconnections are fabricated and measured. The measured results agree well with the simulated results. It can be concluded that the measured insertion and return losses of both single interconnections are better than 0.9 and 10 dB, respectively, in the frequency range from 180 to 240 GHz (28.6%).

An Ultrawideband Three-Dimensional Bandpass Frequency Selective Surface

A new ultrawideband frequency selective surface(FSS) is proposed, which exhibits six resonances to achieve a flat passband. It consists of a three-dimensional (3-D) configuration. However, unlike many other 3-D FSSs, the proposed structure can be assembled through simple steps involving single-layer printed circuit board (PCB) fabrication only. Its unit-cell consists of a wire-loop conducting pattern, printed on a dielectric substrate. The pattern excites four resonances while two resonances are contributed by the dielectric. These six resonances are properly tuned and coupled to form an ultrawide frequency band from 7.53 to 29.45 GHz. It translates to a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$-$</tex-math></inline-formula> 3 dB bandwidth of 119 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\%$</tex-math></inline-formula> . Our design guidelines and discussions are validated through both simulation and measurement results.

A Transmission Line Transition to Extend the Transmission-Line-Excited Magnetoelectric Dipole Antenna Array

A differentially driven transmission-line-excited magnetoelectric dipole (ME-dipole) array antenna is designed for fifth-generation (5G) applications. It is derived from our previous work using a single-layered printed circuit board (PCB) with plated-through-hole technology. The proposed antenna is composed of a 2 × 4 ME-dipole array surrounded by a rectangular cavity. A pair of differential ports feed the antenna. Experiments show that the proposed antenna presents an impedance bandwidth of 26.8% from 55.3 to 72.4 GHz, a 3 dB gain bandwidth of 25% from 55.4 to 71.2 GHz, and a peak gain of 15.3 dBi at 62 GHz. Moreover, the proposed antenna retains all the salient features of the ME-dipole in symmetric radiation patterns and low cross-polarization and back radiation levels.

A New Miniaturized Broadband Multiway and Polyphase Differential Phase Shifter on Single-Layer PCB Substrate

A new technique to realize miniaturized broadband multiway and polyphase differential phase shifters is proposed and studied in this article. In contrast to existing designs based on coupled-line and loaded stubs, the multiway phase dispersions are controlled by susceptances of multiple resonant tanks in this work, which can well enlarge the operation bandwidth (BW) and avoid the unachievable physical sizes in strip width and coupling gap over a large phase shift range on the universal reference line topology. In addition, its phase-shift range can be highly extended by properly allocating resonant frequencies of resonant tanks in each path to be specified different values. The theoretical analysis and design formula are studied, and the synthesis method is presented to determine all circuit parameters. By virtue of the quasi-lumped element technology, the proposed multiway phase shifter can be flexibly implemented on a single-layer printed circuit board (PCB) substrate with a very compact size. For demonstration, a five-way differential phase shifter in 0°-180° range has been designed, fabricated, and tested. Over a BW of 80.4%, the achieved phase shifts are 45° ± 4°, 90° ± 5°, 135° ± 5°, and 180° ± 6.3° with low insertion loss (IL) (<1.05 dB) and small amplitude imbalance (<0.29 dB). To the best of our knowledge, this is the tested widest multiway differential phase shifter in the 0°-180° range up until now. Meanwhile, the whole circuit size, including the substrate, is less than 0.30 $λ_{{g}} $ x $0.26λ_{{g}}$ .

Millimeter-Wave Three-Dimensional Substrate-Integrated OMT-Fed Horn Antenna Using Vertical and Planar Groove Gap Waveguides

A three-dimensional (3-D) substrate integration method by using both the planar dimensions and the vertical dimensions in multilayered substrates for millimeter-wave devices and circuits design is presented in this article. The vertical substrate-integrated groove gap waveguide (SIGGW) is studied first, whose multilayered geometry without metal contact between stacked substrates and wide operating band supporting the single quasi-TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> mode with stable propagation features enables it to be a promising vertical waveguide structure with ease of realization. By simultaneously utilizing the vertical and planar SIGGWs, a fully 3-D substrate-integrated orthomode transducer (OMT) consisting of E-plane power dividers, U-shaped connections, and a turnstile junction that are difficult to fulfill in previous works is successfully implemented in the Ka-band. Its compact geometry and significantly performance improvement demonstrate the merits of the proposed method. After that, the OMT is used for feeding a dual-polarized pyramidal horn antenna also with a 3-D substrate-integrated configuration. The overall multilayered antenna module with experimentally confirmed wide bandwidths, high isolations, and stable radiation patterns can still be fabricated conveniently by employing the standard single-layered printed circuit board (PCB) facilities. Taking the advantages of the flexible design freedom and satisfying operating characteristics, the presented design method and devices are valuable to advanced millimeter-wave applications.

Efficient Transition Hybrid Two-Layer Feed Network: Polarization Diversity in a Satellite Transceiver Array Antenna

In this article, an efficient solution for the development of a new class of two-layer microstrip patch antenna (MPA) with orthogonal polarization ports, based on substrate-integrated waveguide (SIW) through an aperture coupling technique, is presented. Applying the SIW feeding network and aperture coupling to feed the MPA reduces the losses resulting from the feeding circuit and gives a more compact and efficient system. The proposed 4 × 4 array consists of two stacked layers, including an SIW layer as a feeding network and one layer as an antenna layer. The main design feature is the dual orthogonal port to generate different linear polarizations (LPs) (horizontal, vertical, 45°, and 135°). Each layer can be easily fabricated by a single layered printed circuit board (PCB) technology, and then PCB laminates are fixed together using screws. The measured -10-dB impedance bandwidth spans from 9.25 to 10.2 GHz (9.76%). The maximum measured gain at 9.9 GHz is 18.2 dB. The peak radiation efficiency is 84%. The proposed dual orthogonal port antenna exhibits low cost, ease of design, lightweight, high efficiency, and compactness, which makes it a suitable candidate for the polarization diversity in a transceiver for Earth-station applications.

Multistep Transitions From Microstrip and GCPW Lines to SIW in 5G 26 GHz Band

Substrate integrated waveguides (SIW) are a topic of interest for many researchers, due to their power handling capabilities and compatibility with planar processing techniques. These advantages make this technology an attractive candidate for fifth generation of cellular networks applications (5G). Thus, transitions from more common planar technologies to SIW have been designed to obtain a good performance. Several techniques have been used in these transitions, from the use of via holes as probes to the inclusion of lumped elements. We propose the use of cascaded linear tapers as a multistep transition in order to obtain a better performance, optimizing the designs for the 5G n258 band. As result, several transition configurations are optimized, measured and compared to simulations. The design process is performed using an heuristic approach, by just increasing the number of iterations. The optimization of sixteen transition topologies (four different configurations, with four different numbers of steps), is carried out by electromagnetic simulation in CST Microwave Studio. A comparison between the response of the different designs, and the number of iterations used to obtain them, is also presented. Simulations with an in-house full-wave solver are performed to validate the transitions. All the transitions have been manufactured in a low-cost single-layer printed circuit board technology on Rogers 4003C. A microstrip-to-SIW 4-step configuration, tested as a back-to-back prototype, exhibits an insertion loss between 2.0 dB and 2.2 dB and a return loss better than 20 dB dB, from 24.25 GHz to 26.5 GHz, including the effect of the end-launch connectors. Another GCPW-to-SIW 3-step configuration, tested also as a back-to-back prototype, experimentally shows from 24 GHz to 26.5 GHz a minimum return loss of 13 dB, and an insertion loss between 2.6 dB and 2.9 dB. The overall performance of the sixteen configurations validates the usefulness of the proposed design process.

Тепловая модель сквозного металлизированного отверстия печатной платы при од-ностороннем нагреве

Thermal methods of quality control of the plated-through hole (PTH) of printed circuit board (PCB) are based on thermal models. However, known thermal models of PTH take no account of heat transfer to PCB material thus not allowing for PTH heat characteristic tying up with adhesion quality. In this work, an axisymmetric thermal model of a single-layer PCB PTH under one-sided heating conditions is considered. It was shown that the ratio of the temperature increments of the upper (heated) and lower end of the PTH in the considered range of heating power does not depend on the power level. A linear thermal equivalent scheme of the PTH has been proposed, which includes the longitudinal thermal resistance of the PTH metallization, de-termined by the parameters and quality of the metallization layer, the thermal resistance, which determines the convection heat exchange between the ends of the PTH with the adjacent PCB surface and the environment, and the thermal resistance of the area of the PCB material adjacent to the PTH, depending on the quality of the metallization adhesion and the PCB dielectric. Thermal equivalent circuit parameters determined by the ratio of the temperature increment of the upper and lower ends of the PTH and their difference can serve as the basis for the development of a nondestructive inspection procedure for PTH quality control by way of its unilateral heating, for example, by a laser beam.

Hybrid‐fed shared aperture antenna array for X/K‐band airborne synthetic aperture radar applications

The design of X/K-band shared aperture antenna (SAA) single-linear polarized K-band, dual-polarized (linear/circular) X-band 36-elements (6×6) planar array antenna with high gain, and low cost for airborne synthetic aperture radar systems is presented. To reduce the complexity and size of the feed networks, the concept of series-feed centre-fed open stub array with Chebyshev amplitude distribution of −25 dB side-lobe levels (SLL) are employed for K-band design. Two typical frequencies, X-band and K-band of 9.65 and 21 GHz, are chosen (frequency ratio of 1:2.176) in this proposed SAA design on a single-layer printed circuit board. For K-band design, SLL can be controlled by Chebyshev distribution. The amplitude is controlled by the width of the individual patch in the linear array with left and right symmetries. A 50-Ω microstrip line with 0.7λ spacing is used in between the patches for the ±25° scan angle requirement. The measured results are consistent with the simulations and provide a matching impedance bandwidth of 10.36/1.45% at X/K-bands, respectively. The array also has a high aperture efficiency of more than 85%, SLL of (X/K-bands: −18.9/−25 dB), and gain of (X/K-bands: 24.2/17.4 dBi).

PCB-Based Design of a Beamsteerable Array With High-Gain Antennas and a Rotman Lens at 28 GHz

This letter presents a low-cost single-layer printed circuit board (PCB) design of a Rotman lens and an eight-element Yagi–Uda antenna array suitable for radio frequency (RF) beamsteering at 28 GHz. The antenna array realizes 19 dBi gain due to the guiding parasitic elements of each antenna element and a shaped ground plane surrounding the array. The array radiates in a direction parallel to the PCB enabling the possibility for two-dimensional beamsteering by stacking the PCBs. Integrated with an RF switch network, the design has seven switchable beams to the directions $-\text{30}^\circ$ , $-\text{20}^\circ$ , $-\text{10}^\circ$ , 0 $^\circ$ , 10 $^\circ$ , 20 $^\circ$ , and 30 $^\circ$ . The measured realized gain is still as high as 4–10 dBi including losses of the Rotman lens and the RF switches, thanks to the high-gain antenna array design. The array works wideband across 25.5–28.5 GHz where broadside beam gains are better than 8 dBi. This is the first letter in the literature introducing an experimentally verified design of a PCB endfire antenna array at 28 GHz including all necessary components for RF beamsteering, i.e., a Rotman lens and a switch network.

Design of a compact orthogonal fed self‐diplexing bowtie‐ring slot antenna based on substrate integrated waveguide

In this article, a novel design of compact cavity-backed slot antenna based on substrate integrated waveguide (SIW) technology is presented for dual-frequency communication services. A single layer printed circuit board is applied to implement the proposed antenna. The bowtie-ring slot engraved on the SIW square cavity is excited using two orthogonal microstrip feed lines to operate at two distinct frequencies (6.62 GHz and 11.18 GHz). The proposed antenna allows each of these frequencies to be designed independently. A prototype of the proposed cavity-backed antenna that radiates at both 6.62 GHz and 11.18 GHz is fabricated and measured. The port isolation better than 29.3 dB is achieved by utilizing the transmission zeros (TZs), which are produced due to the orthogonal feed lines, TE110 mode and coupling between the TE120 and TE210 modes. The measured peak gains of the proposed diplexing antenna are 5.77 dBi and 5.81 dBi at lower and upper resonating frequencies, respectively. The proposed dual-frequency antenna exhibits the front-to-back-ratio (FTBR) and cross-polarization level greater than 26 dB and 21 dB, respectively, at both resonating frequencies.

Design of a high-selectivity quad-band bandpass filter using open-ended stub-loaded resonator

ABSTRACT This paper proposes a novel resonance structure to design a quad-band bandpass filter using open-end stub-loaded resonator, which consists of four resonant paths capable of independent control. Moreover, the resonators used to the coupled lines in order to create multiple transmission zeros. A quad-band filter that operates at frequencies of 2.1 GHz, 2.7 GHz, 3.5 GHz, and 4.7 GHz is designed with outstanding features including high selectivity without short-circuit stub-loaded resonator and low-cost single-layer printed circuit board process in selecting the individual passband. Good agreement between the simulation and experimental is achieved.