Port Impedance Research Articles

Reply to Comments on “An Asymmetric 2.4 GHz Directional Coupler Using Electrical Balance”

The theory presented by Kumar et al. is based on the assumption that edge-coupled transmission lines (TLs) have infinite even-mode characteristic impedance and is clearly mentioned. Simulation is done to show that better than 10 dB matching can be achieved with a practical TL without using additional TL sections as long as impedance transformed by the even-mode of TL is much lower than the port impedance. The addition of extra quarter-wave TL sections can further improve the matching.

Series fed 3×3 Square Patch Array for Wirel ess Communication Applications u sing CSTMWS

The wireless communications systems have been really develop to the extraordinary performance applications. Present days, the WCS offers extraordinary data rate transmission and preserve rising for advanced data rates equipment. In wireless communication systems applications using various types of micro strip antennas. This paper presents the design of a 3×3 series-fed square micro strip patch array antenna to function at the frequency of 5.4 GHz and 50 ohm line port impedance. The micro strip feed line frequently combines a quarter-wave (λ/4) transformer for matching of impedance. The design of proposed antenna we are expending straight line feed micro strip line feeding technique. This antenna array is based on Rogers RT 5880 loss free material, which is having 2.2 relative permittivity constant. The series fed 3 by 3 square patch array antenna is designed on Computer Simulation Technology (CST) Microwave Studio (MWS) simulation software. After simulation, the antenna presentation features such as return loss, percentage bandwidth, directivity, antenna gain, radiation efficiency, E-Field, H-Field and radiation Pattern are measured.

Control Schemes for Reducing Second Harmonic Current in Two-Stage Single-Phase Converter: An Overview From DC-Bus Port-Impedance Characteristics

The instantaneous input and output power of two-stage single-phase converter are imbalanced, resulting in the second harmonic current (SHC) in the dc–dc converter, dc source, or dc load. This paper revisits the SHC reduction control schemes from the dc-bus port-impedance perspective. The dc–dc converters in two-stage single-phase converters are categorized into two types, namely, bus-voltage-controlled converter (BVCC) and bus-current-controlled converter (BCCC). The dc-bus port impedance of the BVCC is revealed to be approximately inversely proportional to the voltage loop gain. Thus, for reducing the SHC in the BVCC, advanced control schemes are required for increasing the dc-bus port impedance. The dc-bus port impedance of the BCCC is proved to be a negative resistor within the control bandwidth. Hence, for reducing the SHC in the BCCC, the dc-bus voltage ripple should be limited. From the dc-bus port-impedance perspective, the SHC reduction control schemes are reclassified into closed-loop-design-based, virtual-impedance-based, and power-decoupling-based approaches, based on which, different SHC reduction control schemes are carefully reviewed and compared. Finally, potential challenges and issues are discussed.

Vehicle-Level Electromagnetic Compatibility Prediction Based on Multi-Port Network Theory

This paper proposes a new methodology based on the multi-port network theory to predict the vehicle-level electromagnetic compatibility performance. The original EMC problem is firstly converted to a network by separating the electrical large structures and electrical small components. The impedance is proposed to describe the coupling process of network to eliminate the influence of port impedance on network. Based on this network model, the relationship between the exciting sources and the sensitive components is set up using the multi-port network theory. Furthermore, some application problems, such as measurement of parameters, are also discussed. After validated by a bench test, this methodology for vehicle level electromagnetic compatibility was further applied to predict and improve the low frequency radiated emission of an electric vehicle. The application results show that it can be used to predict electromagnetic interference and analyze the main exciting source satisfactorily.

A Novel Uniplanar Balun With Transparent Termination Impedance

In this letter, a novel planar branch line balun with transparent port impedance is presented. The balun is designed based on a symmetric four-port network with an open-ended transmission line stub in the middle of the branch at its unbalanced port side. From the even-odd mode analysis, the equivalent network is derived to be a short circuit under even-mode excitation, and the input impedance looking into the unbalanced port satisfies impedance matching under odd-mode excitation. Unlike previous designs, the equivalent cascaded impedance transformer in the proposed structure is independent to the system reference impedance in odd-mode excitation so that the termination at the unbalanced port is transparent to balanced ports. To prove the design concept, the closed-form equations are derived, and multiple prototypes with termination impedances 35, 50, and $75 ~\Omega $ are simulated, fabricated, and characterized.

A High-Sensitivity Resonant Tangential E-Probe With Loaded Improved Dipole and Embedded Integrated Balun

In this paper, a high-sensitivity resonant probe for capturing tangential $E$ -field component is fabricated on a four-layer printed circuit board. The resonant probe consists of an improved dipole employed to further enhance sensitivity, a resonator made up of open- and short-circuit stubs achieving specific resonance, and an integrated Marchand balun used to transform the differential-mode voltage to the single-end output and match the instrument port impedance match. Compared with the referenced broadband probe, the relative sensitivity of the proposed resonant probe in terms of $\vert S_{12}\vert $ is enhanced by 13.21 and 14.82 dB for simulation and measurement, respectively. The absolute sensitivity in terms of the noise-equivalent field strength (NEFS) is 26.4 ${\mathrm{ dB}} \mu {\mathrm{ V}} ({\mathrm{ Hz}})^{1/2} $ . The measurements of the passive circuits (microstrip lines and coupled lines) and active circuit module are conducted to validate the resonant probe.

Optimization of Micro strip Patch Antenna with Zig-Zag Slot in Broadband Communication

In this paper designed and analysis of the rectangular Microstrip patch antenna for GSM band with frequency band 5.1 GHz. Primarily the designed a conventional unslotted rectangular microstrip patch antenna and measure its different parameters using simulation tools .again introduced a Zig –Zag slotted antenna with dielectric substrate 2.2 and used the centre resonance frequency of 5.1 GHz. The substrate height of the FR4 was 0.787 mm.The comparison results of slotted and unslotted antenna are achieved large bandwidth and gain.The bandwidth of 35.2 % and achieved gain is 7.18 dBi in this poposed designed antenna. To model the probe feed for the microstrip patch we used a lumped port with port impedance equal to 50 ohm. The Zig-Zag antenna developed and its performance are utilized by Zealand IE3D tools. This antenna is used in GSM application and many other communication systems.

Design and Millimeter-Wave Measurement of a Wideband Power Coupling Structure for Sheet Electron Beam Devices

Two power coupling structures based on a Y-type branch waveguide (YTBW) coupler for sheet electron beam devices are presented in this paper. The YTBW coupler is a good choice for the power coupling due to its broad bandwidth property and compact configuration. However, according to the previous studies, it is difficult for a YTBW coupler to obtain good isolation, small port reflection and, meanwhile, high transmission in a broad frequency band. To address this issue, the following two approaches were proposed: 1) introducing multiple branch slots between branch waveguide 1 and branch waveguide 3 of the YTBW coupler to cancel out the electromagnetic (EM) wave propagating toward the isolation port and 2) enlarging branch waveguide 1 at the junction of the three branch waveguides to achieve a port impedance matching and guide the EM wave to propagate to the port connecting with the slow-wave structure. The measured results demonstrated that the bandwidth of port reflection lower than -12.5 dB, isolation coefficient smaller than -12.0 dB, and meanwhile, the transmission higher than -1.0 dB, was 13.5 GHz (50.0-63.5 GHz), corresponding to a fractional bandwidth of 23.8%.

Comments on “A Dual-Band Port-Extended Branch-Line Coupler and Mitigation of the Band-Ratio and Power Division Limitations”

In the above paper ( IEEE Trans. Compon., Packag., Manuf. Technol., vol. 7, no. 8, pp. 1313–1323, Aug. 2017), Maktoomi et al. proposed a dual-band unequal power division branch-line coupler with four arbitrary terminated resistances using the dual-band impedance matching networks and core coupler with equal complex port impedances. However, the definition of transmission phase delay of matching networks provided by authors is incorrect. In this paper, the definition of transmission phase delay of matching networks is clarified.

Analysis and Design of a New Self-Packaged Wideband Balun Bandpass Filter With the Functionality of Impedance Transformation

In this paper, a new self-packaged wideband balun with the high selective bandpass filtering response and impedance transformation characteristic is presented. By virtue of circuit transformations, corresponding two-port equivalent circuit with asymmetrical port impedances is put forward. The analysis results of this two-port network exhibit that the proposed new design is able to achieve a quasi-elliptic equal-ripple response with three transmission poles and four transmission zeros. In addition, the frequency response can be directly determined according to the desired design specifications of impedance transformation ratio k, ripple fractional bandwidth (FBW), and in-band return loss RL. For validation purposes, a demonstrated wideband balun bandpass filter (BPF) working at 2.0 GHz with 50–100- $\Omega $ impedance transformation has been implemented by utilizing the multilayer liquid-crystal polymer (LCP) bonded printed circuit board (PCB) lamination technology. Theoretical, simulated, and measured results are recorded in good agreement, well verifying the design method.

A Novel Dual-Band Zero-Phase True Crossover With Arbitrary Port Impedance

A novel dual-band true crossover that can match with any impedance presented at its input and output ports is proposed in this letter. To break through the conventional 50- $\Omega $ reference port impedance constraint, a planar crossover with a zero-phase delay in the transmission is designed first at a single operating frequency. The proposed single-band zero-phase crossover consists of outer branch lines and inner crossed lines, and the design parameters for each line are obtained by applying the even-odd mode analysis method. Second, the dual-band function is implemented on the proposed zero-phase crossover by replacing each line with dual-band transmission line, which has two series sections and one shunt section. A prototype of dual-band zero-phase crossover operating at 2.15 and 4.1 GHz is designed, fabricated, and measured. The simulation and measurement results agree well with each other to prove the design concept.

A New Design of Filtering Power Dividers With Arbitrary Constant Phase Difference, Impedance Transformation, and Good Isolation

This paper proposes a new class of filtering power dividers integrated with phase shifter and impedance transformer simultaneously for the first time. In contrast to the conventional approaches, the proposed filtering power dividers consist of two asymmetrical generalized bandpass networks, that can achieve arbitrary constant phase difference and good isolation at two output ports. On the one hand, the magnitude and phase properties of two generalized nth-order bandpass networks are systematically studied and fully considered to realize the prescribed power division, filtering function, constant phase difference, and impedance transformation in the co-design. On the other hand, in order to obtain good isolation, the resonator's type and impedance of these two asymmetrical networks are carefully considered and closed-form formula of isolation resistor is also deduced. Theoretical results show that the proposed topology can achieve perfect isolation over entire passband for the arbitrary phase difference. Meanwhile, the synthesis procedures are presented for a quick design process. Finally, two porotypes (90° power divider and 120° power divider) with specified different operation bandwidth (15% and 25%), filter order (3rd and 6th), and terminated port impedances (50Ω and 100Ω) are synthesized, fabricated, and tested to verify the proposed design method and predicted frequency responses. It firstly integrates the power divider, filter, phase shifter, and impedance transformer into single component and has several additional advantages, such as low cost, simple geometry, small phase deviation and amplitude imbalance, and easiness for design and fabrication.

Method of mode decomposition based on virtual ports for circularly polarized micro‐strip antenna

AbstractA design method of circularly polarized (CP) micro‐strip antenna is proposed. The coefficients of eigen‐mode and the axial ratio (AR) are derived based on the cavity theory. The radiation feature can be estimated from port impedance. The optimal feeding position is found by means of virtual port method. During the derivation, corner truncated patch antenna is used to verify the method. A cross‐slotted CP micro‐strip antenna is designed, which is working at GPS band. Then the fabrication and measurement of the antenna are conducted. Its measured impedance, AR, radiation pattern agreed well with the simulation results, which verify high efficiency of this method for CP micro‐strip antenna design.

Wideband Balanced-to-Unbalanced Bandpass Filters Synthetically Designed With Chebyshev Filtering Response

In this paper, two wideband balanced-to-unbalanced (balun) bandpass filters (BPFs) are synthetically designed with three- and four-pole filtering responses, respectively. Based on the simplified even- and odd-mode equivalent circuits of the proposed three-pole balun BPF, the exact impedance value of the cascaded microstrip sections connected with two balanced ports is first determined in order to attain a perfectly matched S-matrix. By the virtue of the modified two-port transmission-line network with asymmetrical port impedances, a quasi-Chebyshev filtering response for this three-pole balun filter is theoretically presented. Next, to improve the in-band performance, especially at the high frequency, a four-pole balun BPF designed with a folded slotline resonator is proposed. Via the virtually short-ended microstrip stubs of the modified two-port equivalent network, the four-pole frequency response can be directly analyzed with the Chebyshev polynomial function. For these two proposed wideband balun filters, their theoretical and simulated results are well confirmed by the circuit model responses with the same impedance values of the simulated microstrip and slotline resonators and the extracted turns ratios of the employed transformers. Finally, two prototype wideband balun BPFs are fabricated and measured to verify our design predictions.

Effect of mutual coupling between feed elements on integrated lens antenna performance

An integrated lens antenna (ILA) equipped with a beam-switching array feed provides beam-steering. This study investigates the effects of the mutual coupling between the feed array elements on the ILA performance. A simulation study of an ILA with two different feed types with varying mutual coupling levels is done. Radiation pattern and boresight directivity of the ILA are in the prime focus of the study. An aperture-coupled microstrip patch antenna (ACMPA) and a stacked ACMPA feeds embedded in an array are used to study the radiation characteristics of the ILA. Results show that changes in directivity and radiation pattern of the feed caused by the mutual coupling have significant impact in the ILA characteristics. However, it is found that the mutual coupling level alone does not predict well the changes in the ILA radiation. Among two feed antenna types with similar mutual coupling variation, the stacked ACMPA feed with less radiation pattern distortion gives better ILA performance compared to the ACMPA feed with significant radiation pattern distortion. Furthermore, impact of the port impedance mismatch of the adjacent inactive antennas on the active element performance of a beam-switching feed network and its corresponding impact on the ILA is investigated.

Novel microstrip quadruplexer with wide stopband for WiMAX applications

AbstractThis work introduces a planar harmonic suppresser microstrip four‐channel multiplexer based on an originally novel geometrical structure. It consists of coupled lines connected to engraved semicircular cells. The realized quadruplexer operates at 3.211, 3.276, 3.38, and 3.491 GHz for IEEE 802.16 WiMAX. Wide stopbands above all passbands are obtained up to about 20 GHz so that fifth harmonics are attenuated properly. The semicircular structures provide quite close channels, which make it appropriate for FDD scheme. Compared to the previous reported quadruplexer, the common port return loss is decreased significantly, where improving the common port impedance matching for very close passbands is an important challenge. To minimize the circuit size, a new matching network consisting of coupled line and step impedance cell is embedded. To verify the designing methodology, the proposed multiplexer is fabricated and measured, where the simulated and measured results are in a good agreement.

A High Linearity High Gain Double Balanced Down Conversion Mixer Using Current Bleeding for Mode 1 of UWB System

This work presents high linearity and high gain CMOS down conversion Gilbert cell mixer for ultra wide band application, designed in 0.18𝜇𝑚 technology. Inductive source degeneration is used at the RF trans-conductance stage of Gilbert cell mixer to improve the linearity of the mixer. Differential LC matching is used at RF and LO stage and current bleeding is used to increases the conversion gain and linearity of the mixer. Output buffer is used at the load to achieve 50 ohm impedance match. The proposed mixer shows low reflection coefficient less than –10 dB for entire band 1, band 2, and band 3 ranges from 3.168 GHz to 4.752 GHz frequency. The proposed mixer works at DC supply of 1.5 volt for low power consumption. Simulation results shows that the mixer achieves the conversion gain of 11.03 dB, 1 dB compression point of -14.65 dB, IIP3 is 0.257 dBm, input return loss is –24.292 dB and measured matched RF (input) port impedance of 48.79 ohm.

A Novel Feeding Network for Quadri-Polarization Antennas With Simultaneously Wide Impedance and Polarization Bandwidth

In this communication, a broadband feeding network for quadri-polarization antennas has been proposed. The feeding network is composed of several passive components, namely two Wilkinson power dividers, slow-wave transmission lines, Schiffman phase shifters, branchline hybrids, and a crossover. With a careful design of each component and an elaborate topology arrangement, the four output ports can transmit signals for antennas with four polarization states in a wideband, i.e., left-hand circular polarization, right-hand circular polarization, +450 and -450 linear polarization. Two antenna implementations based on such a feeding network have been given, and the measured results show that antennas have a bandwidth as wide as 22.7%, within which excellent input port impedance matching, port isolation, realized gain, and polarization purity are simultaneously achieved. The feeding network also has advantages such as completely switch-free, ease of fabrication and implementation, and flexibility for different types of antenna configurations.

A novel planar four-way power divider with large dividing ratio

In this paper, a novel planar four-way power divider with symmetrical simple structure based on microstrip line is presented, and it’s design formulas are deduced. It can achieve arbitrary power dividing ratio, ideal matched ports, ideal isolation between four ports, and the largest power dividing ratio can be 33:1 when the port impedance is 50 Ω and the maximum ring-line impedance is 120 Ω. The relative phase difference of four output ports are 0, π/2,π,π/2 respectively. The structure has ideal matched ports and isolation between four ports. It is suitable for high-power application. Finally, an experimental prototype with power dividing ratio 5.76:5.76:1:1 is simulated and measured respectively. The measured results validate the proposed method.

Supplements to “A Time-Domain Macromodel Based on the Frequency-Domain Moment Method for the Field-to-Wire Coupling”

A macromodel method based on the method of moments was proposed in a previous paper to efficiently and statistically analyze the field coupling to thin-wire structures of arbitrary shape in free space or above the perfectly conducting ground. Through numerical tests and physical insights, it was shown that the extracted macromodel is irrelevant to the port impedances. In this correspondence, a rigorous mathematical derivation is given to prove the irrelevance. The work completes the macromodel method and constitutes its theoretical foundation.