Impedance Of Microstrip Line Research Articles

A compact broadband RF rectifier using two‐stage microstrip lines

AbstractThis paper simulates and measures a compact broadband rectifier for voltage doubler Schottky diode. Among them, a two‐stage microstrip line impedance matching network for voltage doubling circuits is used. The imaginary part of the diode impedance is limited by the short‐circuit branch. The impedance conversion transmission line matches the impedance to 50 Ω. The impedance matching in the circuit is only realized by two‐stage microstrip lines, which reduces the physical size of the rectifier and makes the rectifier more compact. Judging the measurement results from 0.8 to 2.5 GHz, the conversion efficiency is greater than 30% at 0 dBm, the bandwidth is 103%, and the maximum conversion efficiency reaches 66.3% at 8 dBm. In addition, the compact size of the rectifier is 23 × 20 mm2.

Ring Resonator Measurement: Characterizing High Dielectric Constant Materials for the Fourth Industrial Revolution

This study introduces a ring resonator measurement technique targeting high dielectric constant materials. Operating within a frequency range of 0.1 GHz to 5 GHz, the resonator utilizes FR4 substrate and copper conductor. A significant departure from existing methods involves employing a silver-coated ring directly on the sample, mitigating Wheeler's gap issue induced by airgaps across material layers. Furthermore, the research reveals that as dielectric constants increase, microstrip line impedance drastically falls below 25 ohms, potentially leading to inaccurate loss tangent determinations. This paper focuses solely on HFSS simulations to demonstrate the method's feasibility. The proposed technique offers promising prospects for accurately characterizing high dielectric constant materials, thereby facilitating advancements in various applications, particularly within the Fourth Industrial Revolution framework- 5G and 6G technologies.

Tri-Band Circularly Polarized Annular Slot Antenna for GPS and CNSS Applications

A single-feed tri-band circularly polarized (CP) annular slot antenna is presented. The antenna structure is composed of two non-concentric annular slots that are fed by an L-shaped series step impedance microstrip line configuration. The proposed antenna is designed to operate at the L1 & L2 bands of the Global Positioning System (GPS) and the frequency band of the Compass Navigation Satellite System (CNSS). The measured results show that the impedance bandwidths are good for all bands. And the radiation patterns with good CP characteristics are obtained at the three resonant frequencies.

Time domain response of corrugated transmission lines

AbstractIn order to employ periodic corrugated microstrip lines for reducing or suppressing electromagnetic interference in high‐speed or high‐frequency circuits, a precise method is necessary to calculate and measure the characteristic impedance of periodic microstrip lines. The equation for characteristic impedance (depending on frequency) of lossless periodic microstrip lines was obtained based on the transfer matrix method. A time domain pulse was used to measure the instantaneous impedance of conventional microstrip lines, and when the instantaneous impedance does not change with distance, it can be identified as the characteristic impedance of microstrip lines. However, when the time‐domain pulses are employed to measure the instantaneous impedance of periodic microstrip lines, rapid oscillations occur with distance. Therefore, a standard for spacing between adjacent grooves in the microstrip line can be suggested by analysing the interaction between the time‐domain pulses and the microstrip line grooves. Once such a standard is satisfied, many grooves etched along the microstrip line would no longer be distinguished by the time‐domain pulses. Such a principle and method can be used to determine the instantaneous impedance for the microstrip lines that have periodic grooves. On the other hand, when several periodic structures with different lattice constants coexist on a microstrip line, they can also be distinguished via the instantaneous impedance. A time domain reflectometer was used for measuring the instantaneous impedance of periodic microstrip lines, and the measured results are in agreement with the theoretical analysis.

The characteristic impedance calculation method of microstrip line and application in embroidered microstrip line

Presently, it is difficult to measure the characteristic impedance of embroidered microstrip line for its conductive anisotropy directly. The published work had proposed to use S-parameters to estimate the port impedance of a balanced dipole antenna, and it cannot be used to calculate the characteristic impedance of microstrip lines with one arm. Thus, it is still a problem on measuring and obtaining 50 Ω characteristic impedance of embroidered microstrip line. Therefore, taking the reflection coefficient as an intermediate variable, this work proposes to use return loss [Formula: see text] to derive the expression of the characteristic impedance of microstrip line. Combined theoretical calculation with experimental testing on characteristic impedance of the fabric-based microstrip line, the expression of the characteristic impedance was verified. Then, the expression of the characteristic impedance of microstrip line was used to calculate the characteristic impedance of embroidered microstrip line and determine its equivalent substrates. The results show that the fabric embroidered with a single-layer conductive strip is a part of its equivalent substrate, and the fabric embroidered with a double-layer conductive strip is not a part of its equivalent substrate.

Design of High-Order Resonator HTS Diplexer with Very Different FBW

Adopting the deformed stepped impedance micro-strip line structure resonators (SIRs), the external weak coupling hairpin SIR (HSIR) and external strong coupling opening SIR (OSIR) resonators are designed, respectively. These two types of resonators are convenient for creating an ultra-narrow band and broadband filters, respectively, and can broaden the second harmonic passband. A high isolation diplexer without an impedance matching structure is realized by cascading 12-order and 14-order HTS filters composed of OSIR and HSIR resonators with a high isolation T-shaped structure. The diplexer is fabricated on a thin YBCO/MgO/YBCO (a MgO wafer with YBa2Cu3O7 thin film deposited on both sides) film with a dimension of 31.85 mm × 17.28 mm, a thickness of 0.5 mm, and a dielectric constant of 9.8. At 77 K, the measured central frequency of the diplexer is 2395 MHz and 3300 MHz, the fractional bandwidths (FBW) are 1.25% and 24.24%, the out-of-band rejections are greater than 60 dB/MHz, the 2f0 are located at 5.1 GHz and 6.6 GHz, the insertion loss is less than 0.20 dB, and the return losses are better than 16 dB and 15 dB. The diplexer has the advantages of a simple design method, compact structure, low insertion loss, high sideband rejection, and high isolation.

Application of Compact Folded-Arms Square Open-Loop Resonator to Bandpass Filter Design

Folded-arms square open-loop resonator (FASOLR) is a variant of the conventional microstrip square open-loop resonator (SOLR) that facilitates further device size miniaturization by having the two arms of the conventional SOLR folded inwards. This paper highlights the benefits of this brand of compact SOLR by implementing a five-pole Chebyshev bandpass filter (BPF) using compact FASOLR. The test BPF is presented, with centre frequency of 2.2 GHz, fractional bandwidth of 10%, passband ripple of 0.04321 dB, and return loss of 20 dB. The design is implemented on a Rogers RT/Duroid 6010LM substrate with a dielectric constant of 10.7 and thickness of 1.27 mm. The filter device is manufactured and characterised, with the experimentation results being used to justify the simulation results. The presented measurement and electromagnetic (EM) simulation results demonstrate a good match. The EM simulation responses achieve a minimum insertion loss of 0.8 dB and a very good channel return loss of 22.6 dB. The measurement results, on the other hand, show a minimum insertion loss of 0.9 dB and a return loss of better than 19.2 dB. The filter component has a footprint of 36.08 mm by 6.74 mm (that is, 0.26 λg × 0.05 λg), with λg indicating the guided wavelength for the 50 Ohm microstrip line impedance at the centre frequency of the proposed fifth-order bandpass filter.

Design of Six Element MIMO Antenna with Enhanced Gain for 28/38 GHz mm-Wave 5G Wireless Application

The fifth-generation (5G) wireless technology is the most recent standardization in communication services of interest across the globe. The concept of Multiple-Input-Multiple-Output antenna (MIMO) systems has recently been incorporated to operate at higher frequencies without limitations. This paper addresses, design of a high-gain MIMO antenna that offers a bandwidth of 400 MHz and 2.58 GHz by resonating at 28 and 38 GHz, respectively for 5G millimeter (mm)-wave applications. The proposed design is developed on a RT Duroid 5880 substrate with a single elemental dimension of 9.53 × 7.85 × 0.8 mm3. The patch antenna is fully grounded and is fed with a 50-ohm stepped impedance microstrip line. It also has an I-shaped slot and two electromagnetically coupled parasitic slotted components. This design is initially constructed as a single-element structure and proceeded to a six-element MIMO antenna configuration with overall dimensions of 50 × 35 × 0.8 mm3. The simulated prototype is fabricated and measured for analyzing its performance characteristics, along with MIMO antenna diversity performance factors making the proposed antenna suitable for 5G mm-wave and 5G-operated handheld devices.

Channel-Continuous Triplexer With Multiple Transmission Zeros Based on Cascaded High-Pass and Low-Pass Filters

A channel-continuous triplexer (CCT) with multiple transmission zeros (TZs) is designed and processed by cascading the high-pass filter (HPF) and low-pass filter (LPF) through the matching branches. The CCT is realized based on the substrate integrated suspended line (SISL) technology. The out-of-band suppression (OBS) and roll-off rate (ROR) of CCT are improved by the TZs introduced by cross-coupling lines between the nonadjacent branches in the HPFs and high-low impedance microstrip line T junction in LPFs. The experimental results show that CCT covers 4–7 GHz by three continuous bandwidth-identical passbands with the fractional bandwidths (FBWs) of 22.2%, 18.1%, and 15.3%, respectively. The insertion loss within three passbands is less than 1.7 dB, the out-of-band rejection is more than 50 dB, and the ROR is greater than 200 dB/GHz.

A Compact Planar Monopole UWB MIMO Antenna Design with Increased Isolation for Diversity Applications

A compact planar multiple input multiple output (MIMO) antenna with four elements spanning the ultra-wideband (UWB) is proposed for diversity applications. The unit cells are positioned orthogonally to lower the mutual coupling by replicating the single antenna three times. A 35 × 35 × 1.6 mm3 UWB MIMO antenna is provided with a 50-Ω impedance microstrip line on a 1.6-mm thick FR4 substrate. In the radiator and ground plane, some modifications are made to achieve the operating limits of this antenna between the frequencies of 3.1-10.6 GHz, thereby covering the entire frequency spectrum of the UWB with compact size. We conclude from the calculated results that the proposed antenna has high performance characteristics appropriate for UWB wireless indoor communication and diversity applications with compact size.

Fully reconfigurable microstrip bandpass filter with tunable equivalent impedance and six transmission zeros

In this paper, a reconfigurable filter is designed by adjusting the microstrip line impedance for the first time, which breaks the single situation that the resonator can only adjust the electrical length in the previous microstrip reconfigurable circuits. This fully reconfigurable filter loads varactors between three parallel coupling lines to realize the reconfiguration of equivalent impedance. Changing the equivalent impedance of the resonator can use harmonics to introduce transmission poles (TPs) and transmission zeros (TZs), which not only effectively improves the selectivity of the filter but also greatly improves the stopband suppression. Finally, this fully reconfigurable filter can not only tune the center frequency but also the bandwidth. A total of six TZs are introduced, three can be generated by the resonator itself, and the other three are introduced by loading adjustable stubs. The final size of this filter is 0.34 λ g × 0.25 λ g . The measured results are in good agreement with the simulation results.

Method to Improve the Roll-Off and Stopband Response in Low Pass Filter Using Patch Resonators for Modern Wireless Communication

In this paper, several types of patch resonators design procedure are proposed and analysed to improve the roll-off and stopband response in low pass filter. The proposed patch resonators consist of T-shaped patch resonator (TS-PR) that provides instant sharp roll-off and also dual folded T-shaped resonator (DFTS-PR) that improves the roll-off of the previous TS-PR. The transmission zeros of the resonators can be adjusted by varying length and width of high and low impedance microstrip lines. It has been shown that the final design of the patch resonators provides sharp roll-off and acceptable stopband bandwidth by adopting both TS-PR and DFTS-PR. The proposed low pass filter with 3-dB cut-off frequency (fc ) of 5.26 GHz exhibits excellent roll-off rate of 82.2 dB/GHz from 5.5 GHz to 11.7 GHz. Moreover, the transition of the proposed filter is 0.45 GHz which contributes to a sharper transition band from passband to stopband.

Ultra-wide stopband HTS LPF with closed-loop cross-coupled microstrip structure

A compact high-temperature superconducting (HTS) low-pass filter (LPF) with an ultra-wide stopband and a sharp transition band is designed by integrating the fifth-order low-pass filter branch and closed loop cross-coupled (CLCC) microstrip structure. The fifth-order low-pass filter consists of two radial-stubs (RSs), one butterfly-shaped stub (BSs), and two T-shaped stubs (TSs), which can introduce five transmission zeros (TZs) with independently controllable frequency and position, so as to obtain good sideband suppression or upper stopband characteristics. The CCLC microstrip circuit is composed of cascaded high and low impedance microstrip lines, which can widen the width of the upper stopband and realize the ultra-wide stopband characteristic. The operating mechanism of the fifth-order LPF resonator and the CLCC microstrip structure are analyzed by theLCequivalent circuit models. The implemented LPF on a 0.5-mm thick MgO wafer with double-sided YBCO films demonstrates 1-dB cut-off frequency (fc) at 2 GHz and 0.12 GHz narrow transition bandwidth from −1dB to −40 dB. The measured results show a 30-dB harmonic suppression from 1.08fc to 11.7fc i.e., above 23 GHz, a steep roll-off rate of 326 dB/GHz, an in-band insertion loss (IL) <0.10 dB, and a miniaturized size of 0.24λgc × 0.08λgc (λgc is the guided wavelength at the cut-off frequency).

Numerical Hilbert Transform Algorithm for Causal Interpolation of Functions Represented by Cubic and Exponential Splines

This paper presents an algorithm for numerical Hilbert transform of functions represented by cubic and exponential splines, which is suitable for causal interpolation of data spanning several frequency decades. It does not suffer from excessive number of data points due to large frequency span, and does not exhibit aliasing, both of which are characteristic for Hilbert transform algorithms based on FFT. The proposed algorithm was used for causal interpolation of characteristic impedance of microstrip line over conductive substrate, and the results were compared to the output of CausalCat.

Design of compact patch antenna with enhanced gain and bandwidth for 5G mm‐wave applications

A super compact parasitic patch loaded patch antenna with enhanced gain and super wide band is proposed in this study for 5G millimetre-wave (mm-wave) applications. The proposed antenna has hybrid geometry and is constructed using circular and two rectangular driven patches with two semi-circular parasitic patches fed by stepped impedance microstrip line. The two rectangular stubs are incorporated on driven patch to improve the voltage standing wave ratio (VSWR) bandwidth. The two semi-circular parasitic patches are added on the fundamental radiator (driven/main patch) to further enhance the bandwidth to cover the entire Ka-band spectrum for 5G mm-wave requirements and covers 24–40 GHz frequency spectrum with VSWR ≤2. This designed radiator is feasible to be placed inside the multilayered housing systems or can be integrated along with the electronic components existing on the printed circuit board. Furthermore, a four-element modified corporate feed array configuration is constructed and their enhanced gain performances are compared with proposed radiator (single element). Both the prototypes are fabricated and experimentally validated for impedance and radiation characteristics and it is observed that, the simulated and measured responses are in good arrangement. The presented radiating element finds its applications in future 5G mm-wave, 5G base station controlling networks and 5G wideband code division multiple access.

Compact Balanced Dual-Band BPFs Based on Short and Open Stub Loaded Resonators With Wide Common-Mode Suppression

Two balanced microstrip dual-band bandpass filters (BPFs) based on short stub loaded resonator (SSLR) and open stub loaded resonator (OSLR) are presented in this brief, respectively. The center frequencies of the two differential-mode (DM) passbands can be controlled quasi-independently by adjusting the lengths of resonators. Moreover, a stepped impedance microstrip line etched with an interdigital coupling line is utilized to introduce a coupling between the two resonators, which generates two extra controlled transmission zeros (TZs) to obtain better selectivities. Furthermore, balanced microstrip/ slotline (MS) transition structures are employed as feed networks, which can suppress common-mode (CM) inherently while the DM responses are not affected, thereby the design procedure can be simplified significantly. In order to demonstrate the theoretical design, two balanced dual-band BPFs were designed and fabricated. The simulated responses are compared with the measured ones and a good agreement is obtained.

Modelling of Butter worth low pass Stepped Impedance Microstrip line Filter

This paper presents the design of a class of highly selective micro strip low pass filters. The proposed structure is considered for Stepped Impedance Low Pass Butterworth filter of order n=3 and n=5 with cut-off frequency 1.2 GHz and passband ripple of 3.01db [1]. The substrate FR4 having a dielectric constant 4.4 is considered for calculating the physical length of the micro strip low pass filter. The designing equation are solved using MATLAB Software and the results are analysed and compared using IE3D Simulator. The microwave filter is a building block that provides frequency selectivity in various microwave application like mobile, radar, satellite communication systems. The simulated results show the insertion loss and return loss of about -6.65 dB &amp; - 55.49dB for N=3 and -7.23dB &amp;-16.01 dB for N=5.Simulation has also been done for VSWR.

A quintuple mode resonator based bandpass filter for ultra-wideband applications

This paper presents a new configuration of quintuple mode resonator for designing a bandpass filter for ultra-wideband applications. The multiple-mode resonator is constituted by two capacitive ended rectangular stubs and connected with a high impedance microstrip line. Inter-digital coupled feed lines are designed to excite the resonator. Standard analytical approach based on odd-/even-mode analysis is applied to examine the resonant characteristics of the multi-mode resonator. The proposed filter has the characteristics of low insertion loss, wide stopband along with compact size. The bandwidth (|S11| ≤ − 10 dB) of the proposed filter has been observed to vary from 3.11 to 10.63 GHz with low insertion loss value uniform around − 0.8 dB. A wide stopband with attenuation of more than 15 dB (11.27–20 GHz) is observed for the proposed design. The filter occupies a compact area equal to 23.4 mm × 10 mm (about 0.43λg × 0.09λg, where λg is the guided wavelength at 6.85 GHz). The simulated results agree well with the measured results validating the effectiveness of the work.

Miniaturized low‐pass filter based on defected ground structure and compensated microstrip line

AbstractThis article presents a low‐pass filter combining asymmetric π‐type defect structure and microstrip line filter. Traditional single‐form defected ground structure filters often require cascading to have good suppression, which can result in increasing board size and cost. The top layer of the proposed filter is in the form of a stepped impedance microstrip line, and the bottom layer uses a defective structure. Simulation and experimental results show that the filter combining the new defect structure and the microstrip line has a very sharp transition zone and deeper suppression depth than the existing symmetrical or asymmetric defect structure. The proposed structure has an ultracompact size of 356 mm2, and the results show an insertion loss from 0 to 2.2 GHz as low as 0.8 dB and a wide stop band of more than 30 dB from 3.3 to 9.8 GHz.

Design of New Dual-Band Wilkinson Power Dividers With Simple Structure and Wide Isolation

In this paper, a new scheme is proposed for a dual-band Wilkinson power divider (PD) without transmission line (TL) stubs (open- or short-circuited), or additional lumped elements (inductors and capacitors). In comparison with conventional PDs, only three additional TLs are employed. One is utilized to extend the input port, while the others are symmetrically distributed at the two branches. After applying even- and odd-mode analyses to the proposed structure, the exact closed-form design equations for a frequency ratio from 2.0 to 6.5 are derived, considering the largest realizable microstrip line impedance (150 $\Omega $ ). In addition, a new L-type TL with simple structure, compact size, and high design flexibility is proposed to replace the conventional TL to enhance its performance by introducing a transmission zero between the two passbands, resulting in good out-of-band rejection performance. Finally, two dual-band PDs centered at 1.0 and 3.5 GHz are designed and fabricated to verify the proposed design theory. One is based on the proposed structure, while the other incorporates a couple of L-type TLs to replace the conventional TLs. Good agreement with the simulated and measured results can be observed with a low in-band insertion loss and full ports matching. Moreover, the proposed PD also features a wide isolation band with a reference of 15-dB input port return loss. Moreover, the use of the L-type TL can introduce a good stopband between the two passbands, leading to an improved out-of-band rejection performance.