Four-port Structure Research Articles

Miniaturized and high gain circularly slotted 4×4 MIMO antenna with diversity performance analysis for 5G/Wi-Fi/WLAN wireless communication applications

A miniaturized with a high gain four port Multiple-Input Multiple-Output (MIMO) is presented in the manuscript. The presented design contains four radiating patch elements with a Defected Ground Structure (DGS). The shape of the radiating element is identified after the analysis of three stages. The design optimization is performed by changing the diameter of the circle loaded in the patch region and changing the length of the ground layer. The design is investigated for L, S, C, and X frequency band regions. The structure is designed using flame-retardant glass-reinforced epoxy laminate material (FR4) substrate material. The physical size of the four-port structure is 78x50 mm2. Three resonating frequency bands are observed at 2.02 GHz, 5.87 GHz and 11.19 GHz. The structure provides minimum return loss of −10.27 dB, −18.51 dB and −18.59 dB. The proposed design achieves a peak bandwidth of 3.94 GHz, and a maximum gain of 10.03 dBi, Various diversity parameters, including Total active reflection coefficient (TARC), Envelope Correlation Coefficient (ECC), mean effective gain (MEG), Diversity Gain (DG), and channel capacity loss (CCL), have been thoroughly analyzed. The measured and simulated outcomes are compared and analyzed. All performance indicators meet the allowed limits, demonstrating the suitability of the design for 5G, Wi-Fi and WLAN wireless communication applications.

Single-mode distributed feedback lasing using photonic bandgaps to suppress degenerate modes.

We present a method for achieving single-mode distributed feedback lasing, using photonic bandgaps (PBGs) to suppress degenerate lasing modes. These PBGs arise from direct-Bragg coupling and exchange-Bragg coupling due to a passive waveguide placed in proximity to a uniform-grating-active-waveguide lasing structure. Analytic solutions at lasing threshold for this dual-waveguide, four-port structure reveal a high normalized gain margin (e.g., ΔαL = 0.86) accompanied by a low power flatness (e.g., F = 0.001) along the active region, outperforming the λ/4-shifted DFB laser structure. This single-mode lasing mechanism is compelling for both III/V and III/V-on-silicon platforms.

Theory analysis of the optical mode localized sensing based on coupled ring resonators.

Based on Mason's signal flow graph analysis, an analytical model of the optical mode localization based on coupled ring resonators is established. The correctness of the theoretical model is proved by simulation. High sensitivity and common-mode rejection can be achieved by evaluating the modal power ratio from resonant peaks as sensing output. Based on the four-port structure, two output spectrum with mode localization (asymmetric mode splitting) and symmetric mode splitting allows the high-sensitivity sensing and dual-channel calibration to be carried out simultaneously, which can reduce the sensing errors. Monte-Carlo analysis showed that fabrication imperfection changes less than 6% of the performance in 90% cases, thus the construction of practical sensors is possible with appropriate tuning. The optical mode localized sensing has advantages in sensitivity, accuracy, anti-aliasing compared with conventional micro-mechanical mode localized sensor. Various types of high-sensitive sensor can be constructed through coupling parametric perturbation with measurands in different physical domains.

Lumped element balanced multi‐band bandstop filter for ultra high frequency applications

An ultra-compact multi-band balanced (differential) bandstop filter (BSF) topology with all lumped elements has been introduced for the first time in this study. The proposed filter is a four-port structure where each symmetrical bisection is a series cascade of K N -band cells. Each N -band cell comprises of N parallel resonant circuits connected to the same node, through capacitors. K series-coupled N -band filter sections in the symmetrical bisection exhibit a K th order N -band BSF response in differential mode (DM) whereas common mode (CM) signal is minimally affected and maintains a high CM rejection ratio (CMRR). The advantages associated with this engineered structure can be summarised as follows: (i) it can be extrapolated to realise an arbitrary number of DM stopbands; (ii) it does not need any additional component in the symmetry plane to suppress the CM noise; and (iii) it occupies a very small area. For demonstration, a second-order dual-band differential BSF with resonant frequencies 1.15 and 1.36 GHz is designed and fabricated. It offers a rejection level of about 25 dB for each DM stopband and maintains a CMRR value of about 25 dB for both bands. Moreover, it covers an area of only 0.003, where is the guided wavelength at the centre frequency between the two bands.

A Ka-Band Dual-Band Digitally Controlled Oscillator With −195.1-dBc/Hz FoM${_T}$ Based on a Compact High-$Q$ Dual-Path Phase-Switched Inductor

In this paper, a compact, low-loss, dual-path phase-switched inductor suitable for millimeter-wave (mmWave) transceiver subblocks is proposed. The signal path through the structure is determined by the relative polarity of two differential excitation signals applied to the four-port structure. Because inductance is varied by altering signal path through the inductor, signal-path MOSFET switches are avoided. The inductor, therefore, demonstrates high, mode-invariant quality factor, facilitating the design of high-performance dual-band mmWave transceiver subblocks. Based on the proposed inductor, a dual-band Ka-band oscillator is designed in a 65-nm CMOS technology which covers two frequency bands from 14.8 to 18.7 GHz and from 20.8 to 26.6 GHz. The proposed inductor facilitates a widely tunable, dual-band frequency range while maintaining the state-of-the-art phase noise, power consumption, and figure of merit (FoM). The oscillator achieves measured fractional tuning ranges of 23.3% and 24.5% and phase noise of -115.1 dBc/Hz at 2-MHz offset while consuming only 4.8-mW dc power. A peak tuning-range FoM of -195.1 and -194.9 dBc/Hz is demonstrated across the low-and high-frequency bands.

High-speed ultra-compact all-optical NOT and AND logic gates designed by a multi-objective particle swarm optimized method

We have designed high-speed ultra-compact all-optical NOT and AND gates operating at 1550 nm on silicon-on-insulator (SOI) by a multi-objetice particle swarm optimized inverse-design method. The two gates have a similar four-port structure based on an extremely small area of 1.2 × 1.2 µm2. The ultra-small size of device leads to a short respond time less than 0.25 ps. Benefiting from the global optimization of our inverse-design method, our devices have a good tolerance on phase changes of input light. The not gate could keep working while the phase difference of input ranges from 0 to 0.3 π. The situation for AND gate is −0.25 to 0.75 π. Also the maximum contrast ratio is 7.16 dB for the NOT gate and 3.98 for the AND gate, respectively. Moreover, we demonstrate that the design method could have tolerance for small changes in device geometry, which means that our logic gates could remain functional while the pixel side length ranges from 112 to 125 nm. The tiny size, fast response and high robustness make our devices promising for future photonic-integrated circuits.

Fast S-Parameter TAN Model of n-Port Lumped Structures

This paper deals with the fast S-parameter modeling of multi-port lumped structures. The developed model is based on unfamiliar formalism using the tensorial analysis of networks (TAN). The modeling methodology is described with the general abstract topology and different application cases. The methodology consists, first, in elaborating the equivalent graph topology of the considered problem. Then, it is followed by the TAN mathematical abstraction, including, successively, the branch and mesh space analyses. The problem metric can be written with the tensorial Ohm's law expressed in function of the covariant voltage, contravariant current, and the twice covariant impedance in the mesh spaces. The equivalent Z-matrix of the considered multi-port structure is established from an innovative reduction method of the mesh impedance. The S-parameter model is extracted from the Z-to-S matrix transform. The effectiveness of the established fast S-parameter TAN modeling is validated with three cases of proof of concept constituted by TT-cell, the TTT-cell two-port circuit, and four-port structure inspired from the 3D coaxial shielded cable. As expected, an excellent agreement between the S-parameters calculated from the TAN model and simulated from the commercial tools from DC to some hundred's megahertz is obtained. In the future, the developed model is outstandingly beneficial for fast and accurate applications notably for the conduced shielded cable electromagnetic compatibility analysis.

Design of Microwave Baluns With Flexible Structures

In this letter, two types (Type-I and Type-II) of microwave baluns with generalized structures are presented. Different from the conventional transmission-line-based baluns where λ/2 transmission lines or λ/4 microstrip lines are used, the proposed baluns are constructed by transmission lines with arbitrary electrical lengths. Both of the two types of baluns are designed based on a symmetric four-port structure with one of the ports open-ended. Even-odd mode method is applied to analyze the performance of these baluns. Specifically, for the Type-I design, a symmetrical impedance transformer is employed to realize the desired flexible balun function. For the Type-II design, an asymmetric impedance transforming network is applied, and a compact size is achieved. Analytical design equations have been derived for both designs. Based on these equations, two different baluns (Type-I and Type-II) have been designed, fabricated and measured. The measurement results match well with the theoretical analysis, which practically proves the design theory.

A NOVEL PLANAR STRUCTURE FOR IMPLEMENTING POWER DIVIDER OR BALUN WITH VARIABLE POWER DIVISION

A simple and analytical design methodology for a novel planar four-port structure to implement power divider (PD) or balun with variable power division is proposed in this paper. It consists of two difierent 3dB branch-line couplers and one coupled-line phase shifter whose length can be changed to implement variable power division. Difierent from the previous designs, the power divider and balun with variable power division can be realized in only one circuit by changing the electrical length µ0 of the coupled line when the impedance ratio g is selected. According to the ABCD parameters and linear algebra calculation, closed-form mathematical equations for the circuit electrical values and scattering parameters can be obtained. A prototype with this proposed circuit, operating at 2GHz, has been designed and fabricated using microstrip technology. Good agreements between the calculated and measured results verify our design.

Design of a Wideband Balun Using Parallel Strips

A wideband balun designed by exact synthesis is presented in this letter. The designed balun has a symmetrical four-port structure with one port open-ended. It consists of a wideband impedance transformer and a broadband phase inverter, which is realized by connecting bottom and top layer parallel strip through two via holes. To design the wideband impedance transformer, an S-plane highpass prototype has been exactly synthesized with third-order Chebyshev response. The proposed design procedure is very flexible, and it can be easily scaled for other frequency bands. A wideband parallel strip balun operating from 0.72 to 2.05 GHz is fabricated and tested to verify the design concepts. The measured results match well with the design theory.

On-Chip Coupled Transmission Line Modeling for Millimeter-Wave Applications Using Four-Port Measurements

Transmission lines are fundamental elements in millimeter-wave circuits. In this paper, on-chip coupled transmission lines, fabricated in a commercial 0.18 ?m complementary metal-oxide semiconductor process, have been modeled, based on measured 50 GHz four-port scattering-parameters. The two-port open-short deembedding technique and thru deembedding method were successfully extended and applied to the four-port structures presented here. The accuracy of the deembedding techniques was verified by full-wave electromagnetic simulation. Based on the deembedded S-parameters, a SPICE-compatible equivalent circuit model of on-chip coupled transmission lines was extracted. Simulation and measurement results agree well over the entire frequency band from 100 MHz up to 50 GHz.

Experimental and Numerical Investigation of Crosstalk Effect in Coupled Coplanar Waveguides—Part I: Bi-Mode Coupled-Line Representation

The effect of square-wave propagation along coupled coplanar waveguides (C-CPWs) is presented in this paper. Developed numerical tools combining full-wave calculations of the frequency-dependent guided-mode parameters and the network theory formalism enable the determination of port voltages under specified linear termination conditions. Propagation constants and characteristic impedances of coupled lines have been determined for fundamental guided modes using the spectral domain technique combined with Galerkin's procedure. The scattering matrix of the four-port structure has further been used for the calculation of port voltages. Analysis has been performed by taking into account the bi-mode operation resulting from the assumption of the ideal electrical connection of distributed ground plane conductors. Simulation results have been compared with experimental data, and very good agreement has been found, proving the usefulness of the developed numerical tools

High-frequency circuit modeling of large pin count packages

In this paper, a technique is presented for the high-frequency circuit modeling of coupled conductor structures. The method is, in particular, very useful for the modeling of structures with a varying signal/ground configuration. Structures with a large number of conductors (N+1, N>100) are also easy to model, as the method reduces the modeling of the 2N-port to the modeling of two- and four-port structures. Two- and four-port structures are much easier to model since their equivalent circuit model has fewer parameter values. Examples of multiconductor structures are high-density connectors and large pin count electronic packages. The model accurately simulates the electrical properties, such as reflection and transmission of all conductors, and the backward and forward crosstalk to all other conductors.

Fullwave analysis of three and four-port rectangular waveguide junctions

An efficient and accurate technique for the analysis of three- and four-port rectangular waveguide junctions is presented. The technique is based on a generalization of the admittance matrix concept of circuit theory and yields a multimodal description of junctions by means of their generalized admittance matrix. The elements of this matrix are analytically obtained. The multimodal description of three- and four-port junctions allows us to link them with other junctions and/or discontinuities by considering the interactions of the fundamental and higher order modes, thus achieving a fullwave characterization of composite structures. The technique is verified by comparing its results with available measurements of E- and H-plane T-junctions. The E-/H-plane three-port junction which is seldom used, is also analyzed. Finally, the four-port structure magic-T is considered and an analysis of the relative convergence problem for this structure is presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The numerical simulation of the extraction of ion beams from plasma and their dynamics in ionic-optical systems: AF Stekolnikov and OM Ivanov, Minsk Radioengineering Institute, P. Brovka 6, Minsk 220600, USSR

This chapter focuses on real-time SAW convolvers for programmable matched filtering, such as in spread-spectrum communications. This chapter examines three types of real-time convolvers. The first of these is the three-port monolithic waveguide SAW convolver, whose operation is based on acoustic interactions on the surface of the piezoelectric substrate. This type is currently leading the three-port SAW convolver field in applications calling for bandwidths of 100 megahertz or less. The other two real-time SAW convolvers incorporate a silicon semiconductor in close proximity to a lithium niobate substrate such that their operation is dependent on the acoustoelectric interactions of SAW-induced electric fields at the silicon surface. In the order of evolution, these last two are the three-port SAW/ silicon convolver and the more intricate four-port SAW/silicon convolver. This four-port structure finds application in wide-band radar and spread-spectrum communications, such as for packet radio applications. The choice of whether to use a SAW convolver or a linear SAW filter for matched filtering depends on a number of factors. On the credit side, the SAW convolver can provide for a fixed or programmable matched filtering of lengthy coded sequences, well beyond the present range of fixed or programmable transversal SAW filters.

A Microstrip and Stripline Crossover Structure (Letters)

A microstrip or stripline four-port structure which allows two signal paths to physically cross over while maintaining high isolation is described in this letter.

Microstructure detection with the aid of ultrasound: Wegel, G. Feingeräte-Technik Vol 20 No 12 (December 1971) pp 563–566 (In German)

This chapter focuses on real-time SAW convolvers for programmable matched filtering, such as in spread-spectrum communications. This chapter examines three types of real-time convolvers. The first of these is the three-port monolithic waveguide SAW convolver, whose operation is based on acoustic interactions on the surface of the piezoelectric substrate. This type is currently leading the three-port SAW convolver field in applications calling for bandwidths of 100 megahertz or less. The other two real-time SAW convolvers incorporate a silicon semiconductor in close proximity to a lithium niobate substrate such that their operation is dependent on the acoustoelectric interactions of SAW-induced electric fields at the silicon surface. In the order of evolution, these last two are the three-port SAW/ silicon convolver and the more intricate four-port SAW/silicon convolver. This four-port structure finds application in wide-band radar and spread-spectrum communications, such as for packet radio applications. The choice of whether to use a SAW convolver or a linear SAW filter for matched filtering depends on a number of factors. On the credit side, the SAW convolver can provide for a fixed or programmable matched filtering of lengthy coded sequences, well beyond the present range of fixed or programmable transversal SAW filters.

Improved depthfinder display presentation by use of MSI: Brede, R. Electroteknisk Tidsskrift Vol 84 No 20 (November 1971) pp 19–20 (In Norwegian)

This chapter focuses on real-time SAW convolvers for programmable matched filtering, such as in spread-spectrum communications. This chapter examines three types of real-time convolvers. The first of these is the three-port monolithic waveguide SAW convolver, whose operation is based on acoustic interactions on the surface of the piezoelectric substrate. This type is currently leading the three-port SAW convolver field in applications calling for bandwidths of 100 megahertz or less. The other two real-time SAW convolvers incorporate a silicon semiconductor in close proximity to a lithium niobate substrate such that their operation is dependent on the acoustoelectric interactions of SAW-induced electric fields at the silicon surface. In the order of evolution, these last two are the three-port SAW/ silicon convolver and the more intricate four-port SAW/silicon convolver. This four-port structure finds application in wide-band radar and spread-spectrum communications, such as for packet radio applications. The choice of whether to use a SAW convolver or a linear SAW filter for matched filtering depends on a number of factors. On the credit side, the SAW convolver can provide for a fixed or programmable matched filtering of lengthy coded sequences, well beyond the present range of fixed or programmable transversal SAW filters.

Microwave integrated circulators

This paper presents results of several integrated circulators built in microstrip transmission line. The circulators are of the symmetric junction variety and utilize polycrystalline magnesium-manganese ferrites. Three-port circulators and four-port circulators have been built in x-band. The four-port structure is essentially two three-port circulators fabricated end-to-end on a common substrate. Some of the circulators are fabricated by depositing the metallic microstrip circuit directly onto a ferrite substrate. Some are fabricated by pressing ferrite pucks into an alumina substrate on which the microstrip circuitry is deposited. Small permanent magnets are generally used for bias.