Quarter-wave Line Research Articles

A High Efficiency Broadband Gallium Nitride Power Amplifier with Harmonic Control technology

ABSTRACT In order to meet the requirements of high efficiency and broadband for the wireless communication system, a high efficiency and broadband gallium nitride power amplifier (PA) is designed and verified. Using the step-matching structure, its bandwidth has been improved. Furthermore, its input matching network is constructed by connecting several microband lines serially to reduce the matching Q value. Meanwhile, the harmonic control network is designed as the output matching network, which is built by a quarter-wave (λ/4) line open circuit and short circuit microwave lines in parallel. Thus, its drain efficiency (DE)can be improved. This design is simulated and tested at 2.2–3 GHz with the gallium nitride (GaN) process. After measuring, it attains an output power (Pout) of 39.5–41.5 dBm, Gain of 10.5–12.5 dB, DE of 65.1%–78.3% with power added efficiency (PAE) of 64.8%–76.2%.

Planar Rectangular Microstrip Patch Antenna Array with Corporate-Feed Network for Gain Enhancement

Abstract: The design and performance analysis of a inset-fed planar rectangular microstrip patch antenna array with corporatefeed network systems is presented in this paper. This design aims to increase the gain of the rectangular patch antenna through the use of a 16-element planar rectangular antenna array. Each element in this planar array is fed by T-junction power divider networks with quarter-wave transformer lines via the corporate-feed method. The antenna is designed over the operating frequency of 2.4 GHz using the substrate material FR-4, which has a dielectric constant of 4.4 and a loss tangent of 0.002. By the addition of radiating patches in the array design, the gain, directivity and bandwidth also has been improved significantly. The proposed antenna array provides a gain of 9.284 dB, a directivity of 16.2 dBi, and a bandwidth of 0.361 GHz. The designed antenna can be used for wireless applications.

TOWARD ROBUST IN-CAR CONNECTIVITY: SIMULATIVE INSIGHTS INTO THE BEHAVIOUR OF SINGLE PATCH AND 2x2 ARRAY ANTENNAS FOR 2.4 GHZ WI-FI APPLICATIONS

The incessant demand for reliable and robust in-car connectivity drives the evolution of automotive wireless communication. In this pivotal research, we ventured into the realm of 2.4 GHz Wi-Fi applications, emphasising refining antenna designs that focused specifically on the Bio-composite material single patch and the 2x2 array configurations. Our simulations, executed meticulously in CST Microwave Studio, yielded noteworthy findings. The single patch antenna, fortified with a quarter-wave feeding line, delivered an efficiency of 51% and a gain of 2.83 dBi. While promising, its bandwidth limitations beckoned a deeper dive into alternative configurations. Subsequently, our exploration of the 2 x 2 array antenna, enriched with a power divider, stood out as a beacon of improvement. Notably, it exhibited a significant gain elevation, registering at 5.79 dBi. This uptick underscores the 2 x 2 array's superiority over its single-patch counterpart in amplifying in-car Wi-Fi strength and hints at its potential to set a new benchmark in automotive wireless solutions. In synthesis, this research does more than just present empirical data; it offers a roadmap for automotive manufacturers and WiFi solution providers, leading them towards more efficient and robust in-car wireless ecosystems. Beyond its immediate implications, our study lays a strong foundation for future explorations, potentially steering the discourse towards more intricate array antenna designs tailored for vehicular environments.

Performance analysis of the dual-band trapezoidal antenna array for ultra-wideband application

Designing a wireless transmission system with high data rates, high fidelity, and small size is a tough undertaking that has become more popular in the digital age. One of the most important components of wireless communication systems, such as wireless LANs, mobile WIMAX, and Bluetooth devices, is the design of an efficient antenna system. The new circular slot Trapezoidal patch antenna array, which operates in the ultra wide band frequency range of 3.1 GHz to 10.6 GHz, is introduced in this study. The FR4 substrate on which the antenna system is built has a dielectric constant of 4.4. The CST microwave studio suite is used to develop and analyze the performance of the compact structure patch antenna array. Antenna performance is examined in the frequency range of 2 GHz to 5 GHz. Antenna array resonance frequency is 3.1 GHz. By inserting a quarter wave line between the SMA connection and the micro stripline, 50 ohm impedance matching may be achieved. In comparison to previous studies, the intended antenna array has a minimum VSWR of 1.18, a maximum radiation efficiency of ?4.842 dB, and a directivity of 8.645 dBi. Using network analyzer, the test and simulation data were analyzed. The intended use of the antenna array system is for biomedical imaging and body area networks. Abbreviations: UWB: ultra wideband; EMI: electromagnetic interference; MIMO: multiple input multiple output; WLAN: wireless local area network; VSWR: voltage standing wave ratio; AVA: antipodal vivaldi antenna; DGS: defected ground structure; RF: radio frequency.

Design and Characterization of a Traveling-Wave Antenna for Millimeter Applications in the Sub-THz Band

The main challenge in manufacturing antennas in the sub-THz band is their small size, which requires adapted manufacturing tools. This paper proposes a uniform linear 3 × 1 traveling-wave antenna array (ULTWAA) for millimetre applications in the sub-THz band. The designed array allows a continuous beam orientation of ±46.1° in the E-plane. A small quarter-wave line added to the ends of the antenna allows the beam to be oriented towards the inside of the antenna, cancelling out surface waves and adapting the impedance to the scanning angle. Thanks to this device, the waves produced are progressive. The antenna manufactured at 100 GHz measures 13 × 9.7 × 0.125 mm. The measured peak gain is 14.2 dBi with 70% bandwidth. For in-phase radiation, the distances between the antenna units have been adjusted, but the adjustment process is tedious due to the interdependence between the antenna units.

A High-Efficiency Inverse Class-F GaN MMIC Power Amplifier With Compact Output Matching Network

This brief presents a high-efficiency inverse Class-F (Class-F-1) monolithic microwave integrated circuit (MMIC) power amplifier (PA) fabricated with 0.25-lm GaN-on-Si technology. The design is based on a compact output matching network (COMN), which consists of a harmonic control circuit (HCC), an L-section matching circuit and a bias line. In order to reduce the circuit area that make it suitable for monolithic integration, the HCC uses only three transmission lines to achieve the second and third harmonic control. In addition, the conventional quarter-wave bias line is replaced with a shorter, proper one. The proposed COMN simplifies the matching network while realizing Class-F-1 operation, which improves efficiency, output power and reduce chip size. The maximum power added efficiency of 64.5% is achieved at 3.0 GHz, with an output power of 38.4 dBm and a power gain of 10.3 dB.

Reconfigurable multiband nano-antenna design for photonic applications

The Antenna that comprises metal patches set on the Dielectric which is given by coplanar transmission line is known to be a patch antenna. It can also be known as Microstrip patch antenna. The foremost downside is the efficiency of the antenna. A M-patch antenna includes a patch i.e a radiating patch, ground plane on one side and a thin flat metallic region on the other side of dielectric substrate. There are various feed methods such as offset feed, centre feed, inset feed and quarter wave line feed. Microstrip patch antennas have better advantages over conventional antennas. In this paper we develop Multiband Antenna for photonic application. The proposed antenna is designed in a patch model. And in the patch, a cylindrical shape graphene is placed over the patch in which we use this for photonic application. And this antenna is designed in flexible material such as copper tape, Kaptonmaterial and nano materials. Nano based cylindrical antenna was not done previously.In this, we have achieved a gain of 8dB which is comparatively better with other antenna after many implementation.

Low-Loss Single-Band, Dual-Band, and Broadband mm-Wave and (Sub-)THz Interconnects for THz SoP Heterogeneous System Integration

Low-loss single-band, dual-band, and broadband terahertz (THz) interconnects for THz system-on-package heterogeneous system integration are proposed in this article. Transmission lines deployed on a 0.18- <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> m Complementary Metal-Oxide-Semiconductor (CMOS) chip and an integrated-passive-devices carrier, respectively, are coupled electromagnetically as the chip is flip-chip packaged onto the carrier using low-cost gold stud bumps. By doing this, two pairs of quarter-wave coupled lines can be formed to realize a low-loss THz interconnect for transiting a signal from the chip to the carrier. Moreover, single-band and dual-band operations can be acquired by designing the coupled lines to have a length of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\lambda}$</tex-math></inline-formula> /4 and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\lambda}$</tex-math></inline-formula> /4 and 3 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\lambda}$</tex-math></inline-formula> /4 at the frequencies of interest, respectively. The gold stud bumps are also employed to realize a broadband directly-connected THz interconnect which transfers a signal from an on-chip microstrip line to an on-carrier microstrip line in a low-loss and broadband manner. A theoretical analysis using signal flow graphs and Mason's rule is conducted to provide design guidelines. Experimental results show that the proposed single-band, dual-band, and broadband THz interconnects can provide the insertion losses of 1.7, 2.7 and 2.9 dB, and lower than 3.3 dB at 306.5, 140 and 324.5 GHz, and from 140 to 330 GHz, with the return loss better than 10 dB from 256.5 to 330, 140 to 182 and 280 to 330, and 140 to 330 GHz, respectively. To the best of the authors’ knowledge, the proposed THz interconnect demonstrates the first dual-band operation reported thus far.

Application of Theory of Characteristics Modes for Bandwidth Enhancement of a Miniaturized Minkowski Fractal Antenna

This article presents a miniaturized modified Minkowski fractal antenna with enhanced linearly polarized impedance bandwidth (IBW) in the lower frequency region. Applying theory of characteristic modes (TCM) analysis on a second iterated modified Minkowski radiator without feeding structure, modal currents and their corresponding modal fields (radiation patterns) were determined to recognize symmetric dominant modes to be specifically excited to generate the required radiation pattern. It gave direction for choosing quarter-wave microwave line feeding as the feed of choice to excite the four desired modes at 2.7, 5.7, 5.9, and 8.7 GHz and providing excellent impedance matching to generate the very wide IBW. Measured results matched well with simulations done using Ansys HFSS 2020R1. Measured IBW is 9.7 GHz (160%), from 1.2 to 10.9 GHz, with center resonance frequency (frc) at 6.05 GHz, whereas simulated IBW is 9.4 GHz (162%), from 1.1 to 10.5 GHz with frc at 5.8 GHz. The antenna size is 36 × 34 × 1.6 mm3 (0.216λgL × 0.204λgL where at lower resonating frequency frL = 1.1 GHz, λgL is the guided wavelength) with 82.24% reduction in size. This antenna may be utilized for “L”, “S” band and UWB wireless communication.

Electronically Controlled Reconfigurable Antenna for Polarization Diversity

This article describes a novel design for implementing polarization reconfiguration in a simple patch antenna for Wireless Body Area Networks (WBANs) operating at 5.8 GHz industrial, scientific, and medical frequencies. The radiating patch is excited by a quarter-wave matched microstrip line in this structure. The cutting of two quadrilateral-shaped slots on the radiator divides the structure into a square radiating patch and two small triangular patches. Two diodes are embedded across the slot to connect or disconnect the triangular patch from the larger patch. Consequently, the antenna can be reconfigured between linear and Circular Polarization (CP). The antenna is simple and has a compact size of 27 mm × 20 mm × 1.6 mm. A prototype has been made and tested. The result reveals that the antenna produces circular polarization at 5.8 GHz with a good impedance bandwidth of 6.2% (5.56-5.93 GHz). In addition, it has an excellent axial ratio bandwidth of 2.8% (5.71-5.88 GHz). A human tissue model is used in the simulation in order to study the on-body performance of the antenna. The findings indicate that this design is advantageous for off-body communication and significantly improves the reliability of wireless systems.

Metamaterial inspired pin wheel fractal shaped antenna using parasitic split ring resonator for modern wireless applications

This article presents the Pin Wheel Fractal Antenna (PWFA) loaded with Split Ring Resonator (SRR) for X-band and Ku-band wireless applications. The performance of the final iteration of the proposed PWFA has been improved with the loading of SRR in terms of reflection coefficient, bandwidth and gain. The proposed design is fed with 50 Ω microstrip line along with the quarter-wave impedance matching line. To obtain the resonance and radiation characteristics, ground plane length and width of matching line has also been optimized. The bandwidth and gain improved by 26.6% and 31.3% respectively in the first resonance (C-band) and by 16.5% and 8.1% respectively in second resonance (Ku-band) in SRR loaded structure. A prototype of the proposed PWFA is also fabricated and comparison of the simulated and measured results are found in good agreement. The overall dimension of the proposed design is 30 mm × 30 mm, which can be used for various commercial, military and mobile communication systems for C-band and Ku-band.

Wideband unequal filtering power divider with high power dividing ratio based on line‐inserted method

In this study, a type of wideband-filtering power divider (FPD) with high power dividing ratio (PDR) is proposed based on the line-inserted method. The proposed wideband FPD is implemented by inserting a quarter-wave line in front of the conventional wideband FPD. With the inserted line acting as part of each filtering branch, an additional in-band pole is generated, and the requirement for high input impedance can be relaxed. Consequently, both the fractional bandwidth (FBW) and maximum PDR can be enhanced. To enforce the effectiveness of the inserted line, a corresponding design method for the wideband FPD is proposed and demonstrated. Initially, a wideband filter involving the inserted line is synthesized. Then, the synthesized filter is used for implementing wideband FPD using voltage transformers. Finally, the voltage transformers are successfully absorbed into the filtering branches. Examples of 4:1 and 12:1 FPDs operating at 1.8 GHz are designed and fabricated with specified FBWs of 100% and 88%. The measured PDRs are 3.9:1 and 11.2:1 with corresponding bandwidths of 103.9% and 88.3% (|S 11|< –10 dB), respectively. The proposed wideband FPD exhibits a higher PDR, wider bandwidth, equal-ripple response, and filtering embedded compared with the conventional ones.

Coplanar waveguide superconducting microwave power divider: Design, preparation and experimental tests

Power divider is a useful device that divides the power of signal into different subpowers at a certain ratio. The superconducting power divider plays an important role in various superconducting quantum computing circuits and superconducting microwave photon detectors. Therefore, in this paper we investigate how to design and prepare a typical coplanar waveguide superconducting microwave power divider. The parameters are designed by using the odd-even mode method to analyze the transport features of a three-port microwave network. Specifically, the microwave transport properties of the device with a center frequency of 5 GHz and 3 dB power division ratio are simulated. Then, the designed aluminum coplanar waveguide superconducting power divider on silicon is prepared by micro-processing technology and experimentally tested at low temperature. It is shown that the measurement results are consistent with the design parameters. It is noted that the center frequency of the actually prepared power divider is measured to be about 5.25 GHz, which is slightly different from the result of the design and simulation. This difference is probably due to the following main reasons. Firstly, the limited precision of the micromachining process is caused by the fact that the fabricated quarter-wave impedance matching line is etched incompletely, leading the length of the impedance matching line to be shortened. As a consequence, the frequency of the prepared power divider is slightly higher. Secondly, the simulation software is not designed specially for superconducting device simulations, thereby yielding the design parameters slightly different from those of the fabricated superconducting devices. Additionally, a series of attenuations has been used in the experimental test system of the superconducting microwave power dividers for reducing the various noises. This causes the input test signal to weaken, thus the reflected signal turns significantly small. Therefore, none of the &lt;i&gt;S&lt;/i&gt;&lt;sub&gt;11&lt;/sub&gt; parameters of the device can be effectively measured. Finally, neither of &lt;i&gt;S&lt;/i&gt;&lt;sub&gt;21&lt;/sub&gt; and &lt;i&gt;S&lt;/i&gt;&lt;sub&gt;31&lt;/sub&gt; parameters measured in the experiment is the predicted –3 dB, which is mainly due to the imperfections in the welding between SMA connectors and high-frequency transmission lines, and the spot welding between high-frequency transmission lines and power divider samples, and also due to the discontinuities of the high-frequency transmission line and the power divider and so on. All these factors can yield the tested insertion loss of the device. Hopefully, the method in this work can be extended to designing and preparing other passive superconducting microwave devices.

A New mm-Wave Multiple-Band Single-Pole Multiple-Throw Switch With Variable Transmission Lines

This article a new multiple-band single-pole N-throw (SPNT) switch topology suitable for mm-wave applications. Compared to a conventional shunt-type SPNT switch, the proposed SPNT operates in the multiple frequency bands by adopting a variable transmission-line (T-line) structure. The variable T-line (VTL) structure consists of multiple sections of T-line and multiple shunt switches. Therefore, it realizes a variable quarter-wave line at different frequencies depending on the ON–OFF configuration of the multiple shunt switches. To validate the proposed topology, two versions of a triple-band SP3T switch operating at 20, 30, and 40 GHz are demonstrated in a 65-nm bulk CMOS technology. The first version (SW1) employs a minimum number of shunt switches in the VTL structure, thus minimizing the insertion loss. The second version (SW2) includes extra shunt switches in the VTL, thus improving the isolation. The measurement shows that SW1 exhibits insertion loss of 3, 3.4, and 3.6 dB at 20, 30, and 40 GHz, respectively. The isolations are 22.8 or 20 dB at 20 GHz, 18.5 or 21.5 dB at 30 GHz, and 19.7 or 23.5 dB at 40 GHz, depending on the operation mode. On the other hand, SW2 shows improved isolation of 36.2 or 45 dB at 20 GHz, 19.6 or 42.8 dB at 30 GHz, and 22.7 or 38.6 dB at 40 GHz. The insertion losses are 3.6, 3.8, and 3.9 dB at 20, 30, and 40 GHz, respectively.

Compact filtering power dividers with wide upper stopband

AbstractA series of compact filtering power dividers (FPDs) with simple layouts are proposed based on coupling topology. The structure of the presented FPD1 is composed of three resonators and one isolating resistor. These FPDs can be designed based on coupling matrix filter theory. A half-wave transmission line is employed in FPD2 to introduce a transmission zero (TZ) locating at 1.27f0. The FPD3 is designed by replacing quarter-wave transmission lines in FPD2 with quarter-wave coupled lines, which will produce a TZ locating at 1.96 f0 and extend upper stopband bandwidth. For verification, three FPDs centered at 2.45 GHz are fabricated and measured. All measured results are in good agreement with the full-wave simulation results.

Highly efficient broadband class‐J power amplifier using modified multisection quarter‐wave lines and short‐circuited stubs

This study presents a broadband and high-efficiency Class-J power amplifier (PA)-based on a modified multisection quarter-wave lines and short-circuited stubs matching network (MN). It is noted that the modified structure, with good design convenience and great frequency selectivity, especially in the roll-off region between the highest frequency of the desired band ( f H ) and second harmonic of the lowest frequency of the band (2 f L ), is for the first time employed to design PAs with more optimal performance and greater bandwidths (BWs). A step-by-step design procedure of the proposed structure is presented. Experimental results show that using a 10-W Wolfspeed GaN HEMT device, a highly efficient broadband Class-J PA is realised from 1.4 to 2.4 GHz (fractional BW = 52.6%) with measured drain efficiency of 63.0–68.9% and output power of 39.8–40.3 dBm.

A Method of Controlling the Parameters of a Sealed Cable Gland

A methodology for timely monitoring of the electrophysical characteristics and parameters of a sealed cable gland based on inorganic materials is examined. The methodology is applied to assessing the quality of the status of the cable input during actual time of use of the cable line of nuclear physics facilities. The special features of connecting protective shielding systems (double shielding) of nuclear physics facilities are considered. A description of an experimental technique for using a gland for control cables is provided. The results of measuring wave resistance and the attenuation coefficient are analyzed using the quarter-wave short-circuit line method at the carrier frequency. It has been determined that the type of sealed cable gland that has been developed is stable with respect to electrophysical parameters under standard failure conditions and is applicable the input of control cables of nuclear physics facilities.

Design of Length-Saving Multiway Wilkinson Power Dividers

A conventional multiway Wilkinson power divider must include transmission lines with a quarter of the wavelength. The prior miniaturized versions can further shorten the quarter-wave lines by adopting synthesized transmission lines, but the resulted shrunk operation bandwidth has not been considered as part of design. This paper introduces a method of designing the proposed length-saving multiway power divider to achieve targeted bandwidth performance with the minimum required total length. The proposed multiway power divider, including transmission lines with flexible lengths and additional matching capacitors, has the adjustable total length that can be set to the optimum value according to the generated plot mapping the corresponding bandwidths to the selected total lengths. The background principle, the theoretical analyses, and the design procedure of the proposed idea are addressed in detail. The design examples of the four-way, eight-way, and 32-way power dividers are provided. A 1-GHz eight-way power divider prototype based on the proposed design method is fabricated. The measurements, decently matching with simulations and the theoretical prediction, show an expected 51% operation bandwidth with the total length reduced to 72% of the conventional value.

High-Selectivity single- and dual-resonator microstrip filters

New selective properties are revealed of the base section of conventional microstrip filters with circuits based on a four-wire system of coupled quarter-wave lines with one half-wave hairpin resonator. The conditions under which this single-resonator section acquires the characteristics of multi-resonator circuits due to the possibility of formation of four zeros and six operating attenuation poles at the end frequencies are determined. The structure does not contain elements short-circuited to the screen, which determines its high manufacturability. It is demonstrated that high-selectivity compact microstrip filters can be designed on the basis of single- and dual-resonator structures, i.e., the structures with the minimum number of resonators.

UHF and SHF Micro-strip Directional Couplers

The paper gives a review to analyse the outcomes achieved in the field of micro-strip directional couplers within 2010 – 2017. Considers design features of over twenty original or modified quadrature micro-strip directional couplers within ultrahigh (UHF) and super-high frequency (SHF) bands. The focus is on the ways to reduce overall dimensions of traditional loopback, printed and coupled couplers, enhance their use in several frequency bands, suppress higher order harmonics up to the sixth, provide broad-banding operation frequency to several octaves, change a type of the laterally-coupled coupler directionality from the counter-directional to the co-directional and trans-directional ones. The results obtained are achieved due to the following: the change of the quarter-wave line segments for their equivalent micro-strip “П”- and “T”- like structures and their combinations, the quasi-fractal topological implementation of devices, the use of composite transmission lines with the properties of meta-materials, the use of defects of various shapes in the ground plane, the samples in the signal layer of metallization, the low-pass filters in combination version of high-resistance and low-resistance lines, the use of special-form coupling apertures in a multilayer response which allows to compensate for the differences in phase lengths of the segments of connected lines for the even- and odd-order modes, thereby enabling significant improvement of coupler characteristics. The paper briefly describes coupler topologies, equivalent circuits and device layouts. Shows amplitude-frequency and phase-frequency characteristics simulated in computer-aided design systems. Also presents measuring results of the fabricated mock-ups of micro-strip directional couplers. The results obtained may be of interest to the creators of SHF devices and those involved in further investigation to seek and improve couplers of known designs.