Broadside-coupled Microstrip Lines Research Articles

A Novel Wideband 90° Filtering Phase Shifter Using Broadside-Coupled MSLs

This brief presents a novel wideband 90° phase shifter using broadside-coupled microstrip lines (MSLs). Firstly, compared with its traditional counterpart, the proposed one can significantly increase the coupling degree as inquired in the traditional design so as to realize a much wide operating bandwidth in a simple topology. Secondly, for facilitating the design process, this brief introduces a synthesis method to efficiently design the proposed broadband phase shifter with prescribed parameters. Finally, to verify the proposed design, a prototype of the proposed phase shifter is designed, fabricated, and measured. The measured results show that the wideband phase shifter proposed in this brief can achieve 90°±3°, S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> <−22 dB, and fractional bandwidth (FBW) of 80%.

Broadside-Coupled Microstrip Lines as Low Loss Metamaterial for Microwave Circuit Design

The entire microwave theory is based on Maxwell’s equations, whereas the entire electronic circuit theory is based on Kirchhoff’s electrical current and voltage laws. In this paper, we show that the traditional microwave design methodology can be simplified based on a broadside-coupled microstrip line as a low loss metamaterial. That is, Kirchhoff’s laws are still valid in the microwave spectrum for narrowband signals around various designated frequencies. The invented low loss metamaterial has been theoretically analyzed, simulated, and experimentally verified in both time and frequency domains. It is shown that the phase velocity of a sinusoidal wave propagating on the low loss metamaterial can approach infinity, resulting in time-space shrink to a singularity as seen from the propagating wave perspective.

A Flexible 2.45-GHz Power Harvesting Wristband With Net System Output From −24.3 dBm of RF Power

This paper presents a flexible 2.45-GHz wireless power harvesting wristband that generates a net dc output from a −24.3-dBm RF input. This is the lowest reported system sensitivity for systems comprising a rectenna and impedance-matching power management. A complete system has been implemented comprising: a fabric antenna, a rectifier on rigid substrate, a contactless electrical connection between rigid and flexible subsystems, and power electronics impedance matching. Various fabric and flexible materials are electrically characterized at 2.45 GHz using the two-line and the T-resonator methods. Selected materials are used to design an all-textile antenna, which demonstrates a radiation efficiency above 62% on a phantom irrespective of location, and a stable radiation pattern. The rectifier, designed on a rigid substrate, shows a best-in-class efficiency of 33.6% at −20 dBm. A reliable, efficient, and wideband contactless connection between the fabric antenna and the rectifier is created using broadside-coupled microstrip lines, with an insertion loss below 1 dB from 1.8 to over 10 GHz. A self-powered boost converter with a quiescent current of 150 nA matches the rectenna output with a matching efficiency above 95%. The maximum end-to-end efficiency is 28.7% at −7 dBm. The wristband harvester demonstrates net positive energy harvesting from −24.3 dBm, a 7.3-dB improvement on the state of the art.

Slow-Wave Broadside-Coupled Microstrip Lines and Its Application to the Rat-Race Coupler

This letter proposes a type of slow-wave broadside-coupled microstrip lines. The new structure only requires a single-layer substrate and has the independently controllable even- and odd-mode impedances and slow-wave factors by adjusting the corresponding structural parameters. This property greatly simplifies the circuit design. In addition, it provides a large coupling strength. A miniaturized wideband microstrip rat-race coupler with the high isolation and perfect balances is implemented using the proposed slow-wave coupled lines.

Miniaturized Microstrip-to-Waveguide Transition Using Capacitance-Compensated Broadside-Coupled Microstrip Line

In this paper, a compact microstrip-to-waveguide transition using the quarter-wavelength broadside-coupled microstrip line (BCML) is proposed. The 15-dB fractional bandwidth of this transition is 20.95%, which could only cover part of the X-band (8.2-12.4 GHz). In order to enhance the bandwidth, the capacitance-compensated BCML is used to replace the quarter-wavelength BCML. The microstrip-to-waveguide transition using the capacitance-compensated BCML, which is as compact as the transition using the quarter-wavelength BCML, has 37.33% 15-dB fractional bandwidth, almost covering the whole X-band. To verify the simulation results, back-to-back microstrip-to-waveguide transitions using the quarter-wavelength BCML or the capacitance-compensated BCML are fabricated and measured where the measurement results are in good agreement with the simulation results for both designs.

Studies on crossover and broadside‐coupled microstrip bandstop filters

AbstractTwo kinds of two‐layer microstrip structures, including crossover and broadside‐coupled microstrip lines, and their equivalent circuits, are studied based on a quasi‐static analyzing method. The shorting vias from the bottom strips to the ground planes are introduced to achieve bandstop. Simulated and measured results show the validity of the proposed structures and their CAD models for the design of bandstop filters. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 228–231, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11022

Modified broadside-coupled microstrip lines suitable for MIC and MMIC applications and a new class of broadside-coupled band-pass filters

Modified broadside-coupled microstrip lines, suitable for microwave and millimeter-wave integrated and monolithic integrated circuit (MIC and MMIC) applications requiring wide bandwidths and tight couplings, are presented. Their analysis, based on the quasi-static spectral domain technique, is described. Using these broadside structures, a new class of broadside-coupled band-pass filters has been developed at X-band (8-12 GHz) with about 1-dB insertion loss. Fair agreement between the measured and calculated results has been observed even though a major approximation is used. >

Hybrid-mode analysis of a broadside-coupled microstrip line

The purpose of the paper is to present a hybrid-mode analysis for obtaining dispersion characteristics of a broadside-coupled microstrip line. A characteristic equation for a propagation constant is derived via Galerkin&apos;s method in the Fourier-transform domain. It is shown that the dependence of the solution on the basis functions is small. Computed effective dielectric constants in the low-frequency region agree well with other investigators&apos; numerical results, which are based upon the quasi-TEM method. Finally, dispersion characteristics, which are important in practical design, are demonstrated.

Characteristics of broadside-coupled microstrip lines with iso/anisotropic substrates

A quasistatic analysis of broadside-coupled microstrip lines using a series form expression of Green&apos;s function and the method of moments is described. Characteristic impedances, effective permittivities and ratios between phase velocities for the even and odd modes were obtained for various values of strip widths, W/b, spacings between strips, s/b, and for isotropic and anisotropic substrates.

Characteristics of Inhomogeneous Broadside-Coupled Striplines

A variational method for the analysis of inhomogeneous broadside-coupled striplines is described. The data for even- and odd-mode characteristic impedances, effective dielectric constants, and mode phase velocity ratios are presented. It is found that the phase velocity ratio may be varied over the range 1.14 /spl les/ ( V/sub e/ / V/sub 0/) /spl les/ 3.6 for broadside-coupled suspended microstrip lines (BSML) and 0.36 /spl les/ ( V/sub e/ / V/sub 0/) /spl les/ 0.93 for broadside-coupled inverted microstrip lines (BIML) using materials with dielectric constant less than 16 and S/b /spl ges/ 0.05, W/b /spl les/ 2.0. The effect of nonzero strip thickness is also calculated. It is noticed that the effect of thickness is more pronounced for the odd-mode case than for the even mode. Losses are obtained using the incremental inductance rule of Wheeler. The odd-mode attenuation constant is always higher than the even-mode value.