Transmission Line Segments Research Articles

Compact directional coupler with five stubs

In this paper, a compact design of a five-stub microstrip 3-dB coupler with significantly reduced overall dimensions has been developed and investigated. To downsize the conventional layout, artificial transmission line segments, whose characteristics are equivalent to quarter-wave segments at the frequency of 2000 MHz and its neighbourhood, were used. This enables to obtain an area of the compact coupler which is 83.15% less than the conventional one, with just 26.15 % reduction in the operating frequency band.

Lossy flat‐passband signal‐interference microstrip filter

A type of lossy transversal-signal-interference planar bandpass filter (BPF) with a flattened passband is reported in this Letter. The authors exploit in-series-cascaded transversal filtering sections composed of two in-parallel transmission-line segments and series-type lossy hybrid resonators connected at their input / output accesses. The resistors of these lossy resonators by dissipating part of the RF-input-signal energy in the BPF passband region following a complementary frequency-variation profile with regard to the one associated with conventional substrate filter loss allow obtaining an overall flattened transmission band. To experimentally validate the proposed approach, a 2 GHz microstrip prototype of a sharp-rejection lossy signal-interference BPF with a flattened passband is developed and characterised.

Flexible Design Method for Microstrip Bandstop, Highpass, and Bandpass Filters Using Similar Defected Ground Structures

It is well known that the typical low-pass characteristics can be obtained by a cascaded structure of alternating high- and low-impedance transmission-line (TL) segments. On the contrary, this paper focus on modifying this stepped impedance TLs to obtain the bandstop, highpass, and bandpass responses. A basic structure consisting of dumbbell-shaped defected ground structures (DGSs), complementary split ring resonators (CSRRs) DGSs and interdigitated coupling structures is proposed, which can simultaneously satisfy the design of different types of filters. Then, open stubs and short stubs are appropriately selected and achieve the necessary flexibility among the conversions of different frequency responses. Furthermore, different units are ingeniously embedded into the stepped impedance TLs to obtain good performances and small dimensions. By employing the extracted parameters and equivalent circuits, different types of frequency responses are well explained. Finally, the proposed filters are fabricated and measured, the measured results show a great agreement with simulated results.

Исследование амплитудно-частотных характеристик модальных фильтров с пассивным проводником в виде последовательности отрезков линий передачи

Исследование амплитудно-частотных характеристик модальных фильтров с пассивным проводником в виде последовательности отрезков линий передачи

Miniature microstrip branch line coupler with folded artificial transmission lines

The present work is devoted to the miniaturization of a conventional three branch line coupler device in UHF band. The procedure for designing miniature structures based on replacing the microstrip transmission line segment with equivalent structures with the same phase shift is described. These structures are placed in free space inside the coupler. The proposed coupler operates at 1 GHz (UHF band), with good specifications. The area of the manufactured prototype of the three-branch line coupler with open-circuit conditions stubs is 909 mm2, which is 76% less than the size of the conventional device and relative bandwidth is 23.7%. The area of the manufactured prototype of the three-branch line coupler with high-resistance lines with a high-resistance segment in the form of U symbol is 1169.7 mm2, which is 69.1% less than the size of the conventional device and relative bandwidth is 34.1%.

Improvement of Transmission Line Ampacity Utilization by Weather-Based Dynamic Line Rating

Most of the existing overhead transmission lines (TLs) are assigned a static rating by considering the conservative environmental conditions (e.g., high ambient temperature and low wind speed). Such a conservative approach often results in underutilization of line ampacity because the worst conditions prevail only for a short period of time during the year. Dynamic line rating (DLR) utilizes local meteorological conditions and grid loadings to adaptively compute additional line ampacity headroom that may be available due to favorable local environmental conditions. This paper details Idaho National Laboratory-developed weather-based DLR, which utilizes a state-of-the-art general line ampacity state solver for real-time computation of thermal ratings of TLs. Performance of the proposed DLR solution is demonstrated in existing TL segments at AltaLink, Canada, and the potential benefits of the proposed DLR for enhanced transmission ampacity utilization are quantified. Moreover, we investigated a hypothetical case for emulating the impact of an additional wind plant near the test grid. The results for the given system and data configurations demonstrated that real-time ratings were above the seasonal static ratings for at least 76.6% of the time, with a mean increase of 22% over the static rating, thereby demonstrating huge potential for improvement on ampacity utilization.

A fully integrated 4 × 2 element CMOS RF phased array receiver for 5G

This paper presents a fully integrated phased array receiver containing two four element radio frequency (RF) beamforming receivers supporting two multiple-input multiple-output channels. The receivers are designed and fabricated using 45 nm CMOS SOI technology. A 10 bit IQ vector modulator phase shifter (IQVM) is implemented in RF signal paths to control the phase and amplitude of the received signal before combining. Each IQVM provides 360° phase shift control and 17 dB gain variation. An off-chip, simultaneous high-Q impedance matching and bandpass filtering technique for each low-noise amplifiers is presented using non-uniform transmission line segments. Measured downconversion gain at 100 MHz intermediate frequency and noise figure (NF) of a single path are 23 and 5.4 dB, respectively, giving estimated 3.4 dB NF for a single element when simulated PCB and matching losses are taken into account. 1 dB compression point and Input third-order intercept point (IIP3) are − 37 and − 28 dBm, respectively. Each four-element receiver consumes 486 mW DC power from 1.2 V power supply. Total area of two receivers is 5.69 mm2.

Measurement of permittivity and permeability of barium hexaferrite

The paper considers the results of measuring the electrodynamic parameters of a material based on barium hexaferrite with various degrees of substitution Ti(x) = 0; 0.25; 0.5; 1.0. The calculated dependences of dielectric permittivity and permeability obtained by measuring the powder material using the coaxial transmission line segment are presented.

A Broadband Wilkinson Power Divider Based on the Segmented Structure

This paper proposes a topology of a broadband Wilkinson power divider based on the segmented structure. The segmented structure is formed by many transmission line segments in shunt with grounded capacitors and series resistor–capacitor networks. Each transmission line segment has the length of a fraction of a quarter of the wavelength (or $\lambda $ /4) and the summed length of all segments remains $\lambda $ /4. The segmented structure resembles a multiorder matching network and can extend the operation bandwidth through concurrent matching at multiple frequencies. Theoretically, the operation bandwidth can keep increasing with the increased number of segments. Practically, the widest achievable bandwidth is limited by the implementable component values. The theoretical background of the proposed broadband topology is explained. The guideline of designing the proposed power divider is provided. A power divider prototype with the structure of three segments is designed and fabricated. The measurement results, matching the simulations, show the state-of-the-art −20-dB operation bandwidth of 101%, if compared with all the published Wilkinson power dividers having a total length of $\lambda $ /4.

Multi-Stub-Loaded Differential-Mode Planar Multiband Bandpass Filters

A new type of RF $/$ microwave differential-mode planar multiband bandpass filters (BPFs) are presented. Each symmetrical half of the proposed balanced filtering architecture is composed of the in-series cascade of $K$ $N$ -stub-loaded cells through $K-1$ inter-connection transmission-line segments to synthesize a differential-mode transfer function with $N$ $K$ th-order passbands. Additional features of this balanced multiband BPF topology are as follows: 1) generation of transmission zeros at both sides of all differential-mode passbands; 2) high common-mode power-rejection levels within the differential-mode passband ranges; 3) scalability to any number of arbitrary-order differential-mode transmission bands; and 4) lack of electromagnetic couplings in its physical structure. The theoretical foundations of the engineered balanced filter approach, along with guidelines to design the differential-mode transfer function and to attain optimum in-band common-mode power-attenuation characteristics, are expounded. Furthermore, for experimental-demonstration purposes, a third-order triple-band microstrip prototype with differential-mode passbands that are located within the range 1.4–3 GHz is manufactured and characterized.

On the Differential Input Impedance of an Electro-Explosive Device

In this paper, a model for the input impedance of a hot-wire electro-explosive device (EED) based on differential-mode measurements is proposed. The model represents the EED using three transmission line segments in cascade. The characteristics of each segment are estimated according to data reported in the literature and to measurements of the differential-mode input impedance of actual EEDs in the ultrahigh frequency range. The experimental procedure and model are presented in detail. In addition, the impedance measurements and the predictions of the proposed model are compared with previous results reported in the literature.

Design for Testability of SFQ Circuits

Test point insertion and set/scan techniques for enhanced testability in superconductive single-flux-quantum (SFQ) logic are proposed here. Test point insertion reduces the overhead of a set/scan chain while maintaining most of the functionality. Multiple ways of replacing costly (in terms of the number of Josephson junctions) SFQ multiplexers with mergers and blocking gates are proposed. The multiplexer control signals are replaced with a gated clock signal or separate bias networks for both functional and test paths. Clocked blocking gates or current-controlled Josephson transmission line segments are used to disable undesired data inputs. The clocked blocking gates for test point insertion in a 64-bit register requires 35% fewer Josephson junctions as compared to multiplexers. This advantage further increases for current-controlled blocking gates. Set/scan chain and test point insertion techniques are applied to several SFQ circuits to evaluate error characteristics and to provide built-in self-test of SFQ-compatible memory systems.

Performance Analysis of the ITER Plasma Position Reflectometry (PPR) Ex-vessel Transmission Lines

As the design of the ITER Plasma Position Reflectometry (PPR) diagnostic progresses, some segments of the transmission line have become fully specified and estimations of their performance can already be obtained. This work presents the calculations carried out for the longest section of the PPR, which is in final state of design and will be the main contributor to the total system performance. Considering the 88.9 mm circular corrugated waveguide (CCWG) that was previously chosen, signal degradation calculations have been performed. Different degradation sources have been studied: ohmic attenuation losses for CCWG; mode conversion losses for gaps, mitre bends, waveguide sag and different types of misalignments; reflection and absorption losses due to microwave windows and coupling losses to free space Gaussian beam. Contributions from all these sources have been integrated to give a global estimation of performance in the transmission lines segments under study.

Wind adaptive modeling of transmission lines using minimum description length

The transmission lines are moving objects, which positions are dynamically affected by wind-induced conductor motion while they are acquired by airborne laser scanners. This wind effect results in a noisy distribution of laser points, which often hinders accurate representation of transmission lines and thus, leads to various types of modeling errors. This paper presents a new method for complete 3D transmission line model reconstruction in the framework of inner and across span analysis. The highlighted fact is that the proposed method is capable of indirectly estimating noise scales, which corrupts the quality of laser observations affected by different wind speeds through a linear regression analysis. In the inner span analysis, individual transmission line models of each span are evaluated based on the Minimum Description Length theory and erroneous transmission line segments are subsequently replaced by precise transmission line models with wind-adaptive noise scale estimated. In the subsequent step of across span analysis, detecting the precise start and end positions of the transmission line models, known as the Point of Attachment, is the key issue for correcting partial modeling errors, as well as refining transmission line models. Finally, the geometric and topological completion of transmission line models are achieved over the entire network. A performance evaluation was conducted over 138.5km long corridor data. In a modest wind condition, the results demonstrates that the proposed method can improve the accuracy of non-wind-adaptive initial models on an average of 48% success rate to produce complete transmission line models in the range between 85% and 99.5% with the positional accuracy of 9.55cm transmission line models and 28cm Point of Attachment in the root-mean-square error.

Reconfigurable Single/Multi-Band Filtering Power Divider Based on Quasi-Bandpass Sections

A new class of adaptive Wilkinson-type filtering power divider that simultaneously exhibits single/multi-band operation, frequency tuning, and controllable number of passbands is reported. It exploits the incorporation of single/multi-band quasi-bandpass sections into the input/output terminals of the power divider, whose quarter-wavelength-long transmission-line segments are reused as impedance inverters between the quasi-bandpass stages. In this manner, bandpass-type transfer functions are realized at the output nodes along with the power-distribution functionality. For experimental validation, a reconfigurable dual-band prototype that features tunable passbands in the range 0.8–1.2 GHz is designed, manufactured, and tested.

The Technology of the Near-Field Interference Microwave Sensing

We describe the operation of a simple near-field interference microwave microscope. The microscope contains two identical probes which are connected to the ends of segments of the coaxial transmission line. The probes are constructed from an open-ended conical coaxial line and are excited by applied microwave voltage in the frequency range of 0.6 – 7.0 GHz. The computer simulation of the field distribution near the aperture of a separate probe was performed. The test objects are placed in the gap between the probes apertures. The main attention was concentrated on motor fuels to detect other impurities. In particular, diesel fuel was studied with impurities in the form of kerosene and synthetic motor oil in different proportions. It is shown that the microscope can reliably detect these impurities even if their content is relatively small. It was also demonstrated that the microscope can be used for determination of the alcohol quality and spirit-based solutions.

Multi-Way Lossless Outphasing System Based on an All-Transmission-Line Combiner

A lossless power-combining network comprising cascaded transmission-line segments in a tree structure is introduced for a multi-way outphasing architecture. This architecture addresses the suboptimal loading conditions in Chireix outphasing transmitters while offering a compact and microwave-friendly implementation compared to previous techniques. In the proposed system, four saturated power amplifiers (PAs) interact through an all-TL power-combining network to produce nearly ideal resistive load modulation of the branch PAs over a 10:1 range of output powers. This work focuses on the operation of the combining network, deriving analytical expressions for input-port admittance characteristics and an outphasing control strategy to modulate output power while minimizing reactive loading of the saturated branch amplifiers. A methodology for combiner design is given, along with a combiner design example for compact layout. An experimental four-way outphasing amplifier system operating at 2.14 GHz demonstrates the technique with greater than 60% drain efficiency for an output power range of 6.2 dB. The system demonstrates a W-CDMA modulated signal with a 9.15-dB peak-to-average power ratio with 54.5% average modulated efficiency at 41.1-dBm average output power.

Coupled line based unequal dual band power divider

ABSTRACTThis article presents theoretical design of dual band unequal power divider based on coupled line structure. The structure consists of two coupled line segments along with five transmission line segments used to satisfy unequal matching characteristic. The isolation is achieved using a circuit, which is a combination of inductor, capacitor, and resistor. Design equations of proposed power divider and the circuit providing isolation are based on circuit representation of ideal transmission lines. Simulation and measured results are given to verify the theoretical design equations. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:953–956, 2016

Oscillator with Distributed Nonlinear Structure on a Segment of Lossy Transmission Line

We consider a model of self-oscillator with distributed amplifying structure realized on a segment of lossy transmission line. The distributed structure of tunnel diode type generates nonlinearity of polynomial type in the hyperbolic transmission line system. The transmission line is terminated by nonlinear reactive elements at both ends. This means that using Kirchhoff’s law we obtain nonlinear boundary conditions. Then a mixed problem for lossy transmission line system is formulated. We give a new approach to present the mixed problem in a suitable operator form and using fixed point method we prove existence-uniqueness of a solution. To apply the theorem proved one has to check just several inequalities. We demonstrate conditions obtained on a numerical example.

Super-miniaturized Wilkinson power divider using cross-connect meander microstrip lines and conductive vias

A novel three-dimensional (3-D) folded two-way microstrip lines (ML) is proposed for realizing the super-miniaturization of electron devices. The 3-D structure realized with two-way folded ML, which consists of several groups of cross-connected ML and conductive vias, has the potential to have an advanced performance than the corresponding conventional, meandering, and 3-D one-way ML. It can be arranged longer ML in limited spaces. Physical size reduction of the transmission line segments is from λ/4 to λ/32. The Wilkinson power divider (WPD) is designed to operate at the frequency of 433 MHz, has a return loss better than −29 dB, an insertion loss less than 0.28 dB, and isolation larger than +30 dB. The physical size has been reduced by 98.39% when compared with the conventional WPD. Design method about the folded two-way ML is presented for the first time.