Wide Microstrip Line Research Articles

Eight-Element Dual-Band Multiple-Input Multiple-Output Mobile Phone Antenna for 5G and Wireless Local Area Network Applications.

This paper proposes an eight-element dual-band multiple-input multiple-output (MIMO) antenna that operates in the fifth generation (5G), n78 (3400-3600 MHz), and WLAN (5275-5850 MHz) bands to accommodate the usage scenarios of 5G mobile phones. The eight antenna elements are printed on two long frames, which significantly reduce the usage of the internal space of the mobile phone. Each antenna element is printed on both surfaces of one frame, which consists of a radiator on the internal surface and a defected ground plane on the outer surface. The radiator is a rectangular ring fed by a 50 Ω microstrip line which is printed on the top surface of the system board. A parasitic unit is printed on the outer surface of each frame, which is composed of an inverted H-shaped and four L-shaped patches. Each parasitic unit is connected to the internal surface of the frames through a via, and then it is connected to a 1.5 mm wide microstrip line on the top surface of the system board, which is connected to the ground plane on the bottom surface of the system board by a via. Four L-shaped slots, four rectangular slots, and four U-shaped slots are etched onto the system board, which provides good isolation between the antenna elements. Two merged rectangular rings are printed on the center of each frame, which improves the isolation further. The return loss is better than 6 dB, and the isolation between the units is better than 15 dB in the required working frequency bands. In addition, the use of a defected ground structure not only makes the antenna element obtain better isolation but also improves the overall working efficiency. The measurement results show that the proposed MIMO antenna structure can be an ideal solution for 5G and WLAN applications.

Wide Microstrip Line Type Probe With Slits and Permeability Evaluation of Thick Magnetic Material

We have developed a new microstrip line type probe with a wide conductor having some slits to eliminate the measurement error of the demagnetizing effect in thick samples. The slits enhanced the homogeneity of the high-frequency current in the wide direction of the microstrip conductor, which resulted in the application of a uniform high-frequency magnetic field to the sample. Complex relative permeability of thick NiZn ferrite sheet and carbonyl iron particle (CIP) sheet ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times $ </tex-math></inline-formula> 1 mm, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$100 ~\mu \text{m}$ </tex-math></inline-formula> in thickness) has been evaluated accurately using the probe. The measurement error of permeability was evaluated within about 15% in 0.1–20 GHz compared with the conventional Nicolson–Ross–Weir method.

Variable bandwidth, high efficiency microwave resonator for control of spin-qubits in nitrogen-vacancy centers.

Nitrogen-Vacancy (NV) centers in diamond are attractive tools for sensing and quantum information. Realization of this potential requires effective tools for controlling the spin degree of freedom by microwave (mw) magnetic fields. In this work, we present a planar microwave resonator optimized for microwave-optical double resonance experiments on single NV centers in diamond. It consists of a piece of wide microstrip line, which is symmetrically connected to two 50Ω microstrip feed lines. In the center of the resonator, an Ω-shaped loop focuses the current and the mw magnetic field. It generates a relatively homogeneous magnetic field over a volume of 0.07 × 0.1mm3. It can be operated at 2.9GHz in both transmission and reflection modes with bandwidths of 1000 and 400MHz, respectively. The high power-to-magnetic field conversion efficiency allows us to produce π-pulses with a duration of 50ns with only about 200 and 50 mW microwave power in transmission and reflection, respectively. The transmission mode also offers capability for efficient radio frequency excitation. The resonance frequency can be tuned between 1.3 and 6GHz by adjusting the length of the resonator. This will be useful for experiments on NV-centers at higher external magnetic fields and on different types of optically active spin centers.

High-Efficiency Broadband Planar Array Antenna with Suspended Microstrip Slab for X-Band SAR Onboard Small Satellites

In this paper, a high efficiency broadband planar array antenna is developed at X-band for synthetic aperture radar (SAR) on small satellites. The antenna is based on a multi-layer element structure consisting of two dielectric substrates made of Taconic TLY-5 and three copper layers (i.e., the parasitic patch (top layer), the active patch (middle layer), and the ground plane (bottom layer)). The parasitic patch resides on the bottom surface of the upper TLY-5 substrate while the active patch is printed on the top surface of the lower substrate. A Rohacell foam material is sandwiched between the top layer and the middle layer to separate the two dielectric substrates in order to achieve high directivity, wideband, and to keep the antenna weight to a minimum as required by the SAR satellite application. To satisfy the required size of the antenna panel for the small SAR satellite, an asymmetric corporate feeding network (CFN) is designed to feed a 12 × 16 planar array antenna. However, it was determined that the first corporate feed junction at the center of the CFN, where higher amplitudes of the input signal are located, contributes significantly to the leaky wave emission, which degrades the radiation efficiency and increases the sidelobe level. Thus, a suspended microstrip slab, which is simply a wide and long microstrip line, is designed and positioned on the top layer directly above that feed junction to prevent the leaky waves from radiating. The experimental results of the antenna show good agreement with the simulated ones, achieving an impedance bandwidth of 12.4% from 9.01 to 10.20 GHz and a high gain above 28 dBi. The antenna efficiency estimated from the gain and directivity eclipses 51.34%.

Design guidelines for single and dual wide band leaky periodic microstrip line antennas

Leaky wave antennas using periodic microstrip lines are natural choices for versatile beam scanning applications. In this work, a shorted stub and an open stub are simultaneously used in the same unit cell to generate resonant frequencies dependent on the stub dimensions. Placing one such resonant frequency at the second Bragg stop band, a single wideband response is obtained. Next, the stub lengths are tuned to obtain two resonant frequencies which are placed at the second and fourth Bragg stop bands, respectively to obtain a dual wideband response. Design guidelines are outlined for obtaining these wide bands and corresponding radiation regions. Two such geometries with single and dual-band nature are fabricated. The single wide-band antenna has a pass-band from 5.89 to 11.57 GHz with a beam scanning range of −56° to 33°. The dual-band antenna has two pass-bands radiating in the frequency range 5-6.5 GHz and 10.7-14.7 GHz. Beam scanning range in the first pass-band is −72° to −5°. The second pass-band, in part, demonstrates a dual-beam nature with the forward beam scanning from 28.9° to 54.5° and backward beam scanning from −54.5° to 14.76° as the frequency varies from 12 to 14.5 GHz.

An effective third harmonic generator using a left‐handed nonlinear transmisson line

ABSTRACTIn this article, an effective third harmonic generator using a left‐handed nonlinear transmission line (LH NLTL) is presented. The proposed harmonic generator using the LH NLTL is composed of a series of varactor diodes and shunt inductances, which were implemented with a 0.2‐mm wide microstrip line. The harmonic generator was built on a Rogers RO4003 substrate and has dimensions of 12 × 7 mm2. The fabricated LH NLTL provides a maximum insertion loss of 5.2 dB, and a minimum insertion loss of 2.2 dB for a wide frequency band from 2.3 to 18.7 GHz. The measured minimum third harmonic conversion loss was 14.2 dB at an input frequency of 2.5 GHz. When compared to other works, a better third harmonic conversion efficiency is achieved with much smaller size in lower frequencies. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:568–570, 2014

宽微带X射线分幅相机的研制

宽微带X射线分幅相机的研制

The danger of high-frequency spurious effects on wide microstrip line

It has been found that remarkably severe spurious effects can occur in the current excited on microstrip line at moderate to high frequency, when the strip is wide (approximately w/h > 3). This newly observed effect occurs because one or more leaky modes (LMs) approaches the branch point at k/sub 0/ in the complex longitudinal wavenumber plane. When this happens, the attenuation (leakage) constant of these LMs becomes very small. Hence, the LMs can propagate to very large distances along the line with only minimal attenuation. This effect only occurs when the strip is fairly wide, and at certain frequencies. When it occurs, the effect can be disastrous since the continuous-spectrum (radiation) part of the current on the strip then decays very slowly with distance from the source so that the total strip current excited by the source exhibits spurious oscillations out to very large distances from the source. An approximate design rule for predicting this effect is given, which is accurate for wide strips (approximately w/h > 6). The LMs that are responsible for this effect are identified, and the behavior of these modes are studied for different strip widths.

A Wiener-Hopf-type analysis of uniaxial substrate-superstrate microstrip structures

A Wiener-Hopf-type technique in conjunction with the hybrid-mode analysis and a space-domain Fourier transform pair was employed for the solution of the canonical problem of a TEM wave obliquely incident upon the edge and defined by a semi-infinite plate conductor lying at the interface of two uniaxial dielectrics, forming an otherwise grounded double-layer geometry. The single-cover layer and double-layer surface-wave modes' characteristic equations are examined and their cutoff conditions, along with safe conditions avoiding longitudinal-section magnetic (LSM) modes are given. The scattered field components and the TEM-wave reflection coefficient are given analytically in the form of Sommerfeld-type integrals. A thin layers approximation and a numerical integration scheme were adopted for the evaluation of the reflection coefficient. Its expression can be directly used for the analysis of wide microstrip lines and patch antennas printed in a substrate/superstrate geometry. The whole analysis gives a clear physical insight into the problem. Furthermore, a twofold theoretical verification was adopted by either forcing the absence of the superstrate or considering both layers to be isotropic. Numerical parametric Investigations show the effects of either the presence of the superstrate or both layers' dielectric anisotropy.

Line-loss and size reduction techniques for millimeter-wave RF front-end boards by using a polyimide/alumina-ceramic multilayer configuration

This paper proposes a concept for constructing low-loss and small-size millimeter-wave RF front-end boards by using a polyimide/alumina-ceramic multilayer configuration. The thick polyimide layer enables us to design low-loss wide microstrip lines (MS's). Moreover, the board size can be reduced by compactly arranging all RF and dc lines in the intermediate layers of the polyimide/alumina-ceramic substrate. The size of a prototype board designed for the quasi-millimeter-wave region is 30 mm/spl times/30 mm. In experiments, it showed 23.2-dB linear gain and 7.4-dBm P/sub -1/ RF output power in transmitter (TX) mode, and 3.1-dB linear gain and -20.1-dBm P/sub -1/ IF output power in receiver (RX) mode. These performance levels agree well with predicted values. This paper further discusses applications to the integration of passive circuits fabricated in the substrate. The proposed configuration has enough potential to integrate all monolithic microwave integrated circuit (MMIC) chips, dc-bias integrated circuits (IC's), and passive circuits, and can improve the total performance in terms of the RF characteristics, board size, and fabrication cost.

A study of the transverse current contribution to the characteristics of a wide cylindrical microstrip line

By considering both the longitudinal and transverse components of the surface current on the microstrip line, the effective relative permittivity and the characteristic impedance of a wide cylindrical microstrip line are analyzed. Theoretical results are calculated with the use of a full-wave formulation and a moment-method computation. Experiments are also conducted to verify the calculated results, and the contribution of the transverse current component to the characteristics of a wide cylindrical microstrip line is discussed. © 1996 John Wiley & Sons, Inc.

Propagation in layered biased semiconductor structures based on transport analysis

A transport-field parallel-plate formulation and solution method to determine the small-signal propagation constant is given for wide microstrip lines over an inhomogeneously doped semiconductor substrate of small transverse dimensions. Included in the detailed transport model are two carrier species, recombination-generation mechanisms, DC and AC field-dependent mobilities and diffusion constants, and boundary condition contact effects. A transverse DC bias condition is applied. Structures numerically simulated are a voltage-variable GaAs distributed Schottky-barrier phase shifter and a transmission line over an Si bipolar junction. Numerical data based on a finite-difference technique are generated on carrier densities, electric potentials and fields, and current densities. Propagation constant calculations compared favorably to those calculated by both full-wave field analysis and moments-of-the-Boltzmann-equation analysis for some less general cases. Propagation constant results for the GaAs structure are compared with available experimental data, and good agreement is obtained. >

Coupling across gap in thick microstrip line

Experimental measurements have been made of the capacitive effects of a gap in a wide microstrip line with a thick, low permittivity substrate. The results reveal negligible fringing capacitance at each edge of the gap. Derived values of the coupling capacitance across the gap are also presented.

Microwave Components Using Ferrimagnetic Pastes

Ferrimagnetic pastes have been developed using Mg-Mn, Mn-Ni, Li, and Cu-doped magnesium ferrite aluminate and YIG powders. Isolators and circulators fabricated using these pastes on alumina substrates have been partly reported earlier. These devices exhibited higher insertion losses compared to those on YIG/ferrite substrates. Photomicrographs of Li-ferrite have been taken and these reveal cracks which may be responsible for high loss. The thermal co-efficient of expansion has also been found for this paste.Thick-film dual directional couplers have been fabricated using the field-displacement phenomena in wide microstrip lines. The coupling from one auxiliary line to the other on either side of the wide line can be changed by switching the polarity of the magnetic field. The performances of these devices have been compared with those on ferrite substrates over the frequency range from 2 to 8 GHz. A bandwidth of 600 MHz for a 15-dB coupler has been obtained with Li-ferrite paste.

Asymptotic Eigenequations and Analytic Formulas for the Dispersion Characteristics of Open Wide Microstrip Lines

Through the matched asymptotic expansions technique, asymptotic eigenequations for the even and odd modes of an open wide microstrip transmission line are derived. The eigenequations, and simplifications thereof which do not involve integration, can he solved easily for the effective permittivity. Even though d/W is assumed to be small, the solutions are good even if d/ W/spl cong/0.8 when compared with the numerical results of Jansen. From these eigenequations, asymptotic formulas for the effective permittivity can be derived which are excellent when d/ W/spl cong/0.2. When the frequency goes to zero, we reproduced the asymptotic formula derived under the quasi-TEM approximation in [8]. The asymptotic analysis provides good physical insight into the problem, otherwise unavailable from numerical analysis.

A linearly dispersive magnetostatic delay line at X-band

Experimentally verified calculations which have been performed show that the group delay versus frequency characteristic for magnetostatic forward volume waves in a YIG film of thickness t spaced an equal distance t from a ground plane can be essentially linear over a substantial frequency range. In particular, results are reported on an experimental YIG magnetostatic delay line which showed a linear delay ranging from 50 to 230 nS/cm (linearity ±3 nS/cm) over a 1 GHz bandwidth at X-band frequencies. The 20 μm thick YIG film, grown epitaxially on GGG, was spaced 20 μm above a ground plane using an alumina dielectric. The alumina was fabricated by: (a) thinning a conventional substrate by grinding and polishing; or (b) depositing Al 2 O 3 by rf sputtering. Input and output transducers were simple 5 mm long by 50 μm wide gold microstrip lines defined in 5 μm thick gold and open circuited at one end. Results obtained using a network analyzer were in close agreement with the theoretical calculation. The characteristic observed represents a potential pulse-compression factor of 230.

Approximate calculation of radiation from open-ended wide microstrip lines

Theoret ca results as given in the literature for the open-ended dielectrically loaded parallel-plate waveguide are used to calculate the input reflection coefficient of open-circuited wide microstrip lines. Numerical computations are in good agreement with measurements for a stripwidth/substrate-height ratio of greater than 3.