Coupled Microstrip Research Articles

E-shaped Aperture Coupled Microstrip Patch Array Antenna for High Speed Downlink Applications in Small Satellites

E-shaped Aperture Coupled Microstrip Patch Array Antenna for High Speed Downlink Applications in Small Satellites

Novel Compact Coupler With Tunable Frequency, Phase Difference, and Power-Dividing Ratio

This letter proposes a novel compact coupler with simultaneously and continuously tuned frequency, output differential phase, and power-dividing ratio (PDR). In addition to multifunctionally tunable capabilities, this microstrip coupler is only one-tenth the size of the state-of-the-art coupler based on the coupled-line structure. Coupler analysis and design equations will be provided with thorough discussion. The fabricated prototype achieved the frequency, differential phase, and PDR tuning ranges of 1.2–2.4 GHz, −64° to −112°, and 0–12 dB, respectively. Moreover, the same coupler can be reconfigured to be a 180° coupler with the measured frequency tuning range of 1.3–2 GHz and PDR tuning range of −8.3 to 11.1 dB.

Improved Analytical Model for a Proximity Coupled Microstrip Patch Antenna (PC-MSPA)

This article presents an accurate full analytical model to assess the impedance response of a proximity-coupled microstrip patch antenna (PC-MSPA). An improved formulation of the patch resonant frequency is used to calculate the quality factor, resonant resistance, and feeding circuit parameters of the antenna. The proposed model also assesses the PC-MSPA impedance response while considering the fabrication constraints. For the validation of the proposed model, at first, the antennas are simulated for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S$ </tex-math></inline-formula> -, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C$ </tex-math></inline-formula> -, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$X$ </tex-math></inline-formula> -bands. Then, two prototypes are fabricated and measured. The proposed model predicts the antenna resonant frequency and impedance bandwidth with less than 1% error.

Compact balanced tri‐band bandpass filter based on stub loaded resonator with high selectivity

A compact balanced microstrip tri-band bandpass filter (BPF) using short and open stubs loaded resonators (SOSLRs) is achieved in this article. Three differential-mode (DM) passbands can be adjusted by properly controlling the dimensions of the loaded short and open stubs, and the first and third DM center frequencies can be implemented independently. By introducing interdigital coupling microstrip lines, five transmission zeros (TZ) are implemented to achieve a higher selectivity. The positions of TZs can be controlled by adjusting the coupling gaps between SOSLRs and interdigital coupling microstrip lines. In addition, balanced microstrip line to slotline transformation structures is introduced as the feed structure, which can be used to block the common-mode (CM) transmission inherently. Therefore, the DM performances are independent from the CM responses, which can simplify the design procedure significantly. For demonstration, a balanced tri-band BPF centered at 1.57, 2.45, and 3.5 GHz was fabricated and measured. Comparison with other reported balanced BPFs indicates that the proposed design exhibits the advantages of high selectivity and good CM suppression responses.

Design, Optimizing and Improvement of Microstrip 5G Patch Antenna Parameters Using Keysight Advanced Designed System (ADS)

This paper described the microstrip Patch antenna of 5G mobile phone with calculation, simulation, and optimization method by using the ADS Simulation software. The patch antenna sized could be applied for various applications and designed wideband, multiband frequency operation. Bandwidth improvement of 3500 MHz is progressed after optimization and the patch can operate for wideband application. In this paper, the calculation method of inset feed patch antenna, designed with simulation by using the calculation method. However, some of the calculations are matched the designed frequency. Therefore, we optimized the design with length only. Moreover, the author implemented the designs that the MLIN (Microstrip Line) is based on the patch distributive line and Asymmetric Edge Coupled Microstrip Lines is designed as the MACLIN3 and MLOC mean microstrip location design.

Compact broadband high‐efficiency power amplifier using terminated coupled line filter matching network

This article presents a compact broadband high-efficiency power amplifier (PA) with a filtering structure. Unlike the cascaded filter behind the traditional PA, the proposed cascaded branch load coupling microstrip line structure is used to design the output matching network (OMN) of the PA. It plays the roles of impedance matching and filtering, which is called a filtering OMN, the overall size of the circuit will be reduced. Two coupled microstrip lines cascaded are used to extend the working bandwidth, and a microstrip line is loaded to the port of the coupled microstrip lines to ensure high selectivity and good out-of-band performance. For verification, a broadband high-efficiency PA is designed and manufactured by using CGH40010F GaN HEMT. Measurements demonstrate that in the range from 1.2 to 3.6 GHz, the saturated output power is from 39.8 to 41.8 dBm, the drain efficiency (DE) with a 62%–73%, and the gain is between 9.9 and 11.7 dB.

Compact 4 × 4 Proximity Coupled Microstrip Fed UWB Stepped Slot MIMO Antenna Having Triple Band Rejection

The presented antenna is a novel highly isolated compact four-element Multiple Input Multiple Output (MIMO) antenna with common ground, which can reject three undesired bands effectively for Ultra-Wideband (UWB) Communication. The overlapping of narrowband communication systems with the UWB spectrum makes radio signals interfere. Therefore, the proposed antenna is designed with triple-band rejection capability. The antenna consists of four feedlines and a common ground surface which acts as the main radiator. The four elements of the antenna are kept orthogonally to exploit polarisation diversity, resulting in high isolation. The presented antenna is having size = 44 × 44 mm2 and printed on FR4 substrate. A spiral slot was introduced in the ground surface which behaves similarly as a band-stop filter (BSF) and rejects the X- band for Uplink Satellite Communication. For rejecting WiMAX and WLAN band, the modified trident shape of the microstrip line is used. Also, Defected Ground Structure (DGS) is used for the isolation (> 23 dB) enhancement. Simulation and measurement results are quite similar. The proposed antenna is used for small handheld communication devices.

High-Q Hg-anapole resonator with microstrip line coupling for high-precision temperature sensing applications

In this paper, to achieve a high-precision temperature sensing, a modified anapole resonator based on the liquid–metal (Hg) with high Q-factor and large thermal-sensitivity properties is proposed. The high-Q resonance of the designed Hg-anapole resonator is excited by a simple microstrip coupling line with large electromagnetic energy coupling rate. The detailed numerical optimization and experimental demonstration are discussed, and the measured temperature sensitivity of 17.14 MHz/°C and figure-of-merit (FOM) of 0.3/°C are achieved based on the proposed Hg-anapole resonator. This kind of liquid high-Q metamaterial unit can be widely used to realize the high-precision sensing.

Symmetrically Direct Coupled Stacked Broadband Microstrip Antenna

ABSTRACT A technique employing the use of directly coupled stacked patches to increase impedance bandwidth with reduced cross-polarization is proposed in this paper. The top stacked multi-resonator configurations are directly excited by employing metallic shorting posts (vias) between the metallic patches. In stacked directly coupled MSA, a bandwidth of 25.8% and a gain of 8.8 dBi with a gain variation of ±0.2 dB over the band are achieved. The cross-polar levels for this configuration are less than −15 dB and −5 dB at lower and upper frequencies, respectively. To suppress the cross-polar components, a symmetrically direct-coupled stacked MSA design is proposed. In this configuration, a bandwidth of 26.1% and a gain of 9.3 dBi with ±0.3 dB variation over the entire bandwidth are achieved. The cross-polar levels are significantly suppressed up to −25 dB and −16 dB at lower and upper frequencies, respectively. The proposed antenna configurations are designed and fabricated. The experimental results agree with the simulated results.

Introductions about Microstrip Couplers and Power Splitters

Microstrip couplers and power splitters are widely used electrical components in the field of microwave technology, which has the function of dividing one wave into multiple waves with same magnitudes but different phases. In this essay, 5 typical types of couplers and power splitters are introduced, with their applications, layout designs, effect on the wave, advantages and weaknesses. Couplers and power splitters are labelled with their output wave phase differences and their voltage magnitude transfer ratio. In this essay, all the couplers introduced are 3dB couplers, which means that the output voltage is decreased by 3dB. The Wilkinson power splitter has an output phase difference of 0 degree, the monolithic multilayer 2-line microstrip directional coupler, the Lange coupler, the microstrip branch-line coupler have output phase difference of 90 degrees, and the planar Marchand balun has output phase difference of 180 degrees. The microstrip rat-race coupler has 2 divider modes and 1 combiner mode, where in the divider mode the phase difference could be set as 0 degree or 180 degrees. Therefore, in the design of microwave circuits, the type of coupler should be carefully chosen according to the working characteristics, the structure features and the working conditions of couplers.

Analytical Model to Calculate the Impedance Bandwidth of a Microstrip Patch Antenna (MPA)

The aim of this paper work to design and analyzed a compact size Microstrip patch antenna. The conducting patches like rectangular and circular configurations are most commonly used for configurations. Mostly microstrip patch antenna is performed with narrow bandwidth. Here, an analytical mathematical model is used to calculate the impedance bandwidth, which improves the bandwidth of an antenna. In this paper Impedance Bandwidth of an Aperture Coupled Microstrip Patch Antenna (AC-MPA) using an accurate analytical model. The proposed mathematical model is used to calculate the impedance bandwidth of the antenna with high accuracy. MSP is mainly focused on the design of the compact-sized wideband Microstrip antenna. The return loss is -36.8785dB from 2 GHz to 4 GHz frequency with a bandwidth of 0.28 GHz. A maximum gain of 20 dB is achieved at 3.45 GHz frequency.

Compact Filtering Balun With Wide Stopband and Low Radiation Loss Using Hybrid Microstrip and Substrate-Integrated Defected Ground Structure

In this letter, a novel hybrid microstrip and substrate-integrated defected ground structure (SIDGS) are proposed for filtering balun design. Coupled microstrip and SIDGS resonators can not only achieve 180° phase imbalance with filtering response but also realize wide stopband and wideband low radiation loss. In addition, the feature of stacked substrate packaging could reduce the size of the circuit and be flexible for integration. To verify this mechanism, a filtering balun operating at 3.08 GHz with 3-dB fractional bandwidth (FBW) of 45% is proposed based on hybrid microstrip and SIDGS, which exhibits the in-band amplitude- and phase-imbalances of ±0.5 dB and ±0.4°, respectively. The stopband extends to 18 GHz with the rejection level of 20 dB, whereas the measured total loss (i.e., including radiation, metal, and substrate loss) is less than 15% up to 15.3 GHz.

A Low Profile Dual-Band High Gain Directional Antenna for Anti-Interference WLAN Station Applications

This paper presents a low-profile dual-band antenna with directional radiation characteristics for wireless local area network (WLAN) applications. The proposed directional antenna is composed of a coupling microstrip line, two F-shaped strips, two rectangular strips, and a defected ground plane. The measured impedance bandwidth of the proposed antenna is 180 MHz (2.33–2.51 GHz) and 830 MHz (5.09–5.92 GHz), which can cover Institute of Electrical and Electronic Engineers (IEEE) 802.11 a/b/g frequency bands. The dual-band antenna exhibits a desirable directional radiation patterns in the vertical and horizontal planes with the peak gain of 6.55 dBi in the lower frequency band and 8.1 dBi in the higher frequency band. The measured antenna efficiency is 70% at 2.4 GHz and 84.5% at 5.5 GHz. The proposed dual-band WLAN station antenna is designed on a FR4 substrate with overall dimensions of 69 mm × 50 mm × 1.6 mm.

Analysis of Side Coupled Microstrip Filters Using Three Dimensional FDTD with Berenger Perfectly Matched Layer (PML).(Dept.E)

Analysis of Side Coupled Microstrip Filters Using Three Dimensional FDTD with Berenger Perfectly Matched Layer (PML).(Dept.E)

A Compact Helix Antenna With Wide Axial Ratio Bandwidth Using a Spiral Microstrip Coupling Feedline for GNSS Applications

A compact quadrangular prism-shaped slot helix antenna with wide axial ratio (AR) bandwidth using a spiral microstrip coupling feedline is presented. The proposed antenna is constructed with FR4 substrate copper-clad plate with four slots symmetrically etched on the substrate exterior surface and a spiral microstrip coupling feedline printed on the substrate inner surface. The electric field and equivalent magnetic current excited by the spiral microstrip feedline in slots are analyzed. The wide AR bandwidth is obtained. The proposed antenna has a small dimension of 0.156λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.156 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.182 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> (λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the free-space wavelength at the center frequency). Its measured -10 dB |S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> | bandwidths and 3 dB AR bandwidths are 1525-1662 and 1497-1630 MHz, respectively. It generates right-hand circular polarization (RHCP) without a complicated feeding network. It promises a good use in Global Navigation Satellite Systems.

Improved Modeling of Microwave Structures Using Performance-Driven Fully-Connected Regression Surrogate

Fast replacement models (or surrogates) have been widely applied in the recent years to accelerate simulation-driven design procedures in microwave engineering. The fundamental reason is a considerable—and often prohibitive—CPU cost of massive full-wave electromagnetic (EM) analyses related to solving common tasks such as parametric optimization or uncertainty quantification. The most popular class of surrogates are data-driven models, which are fast to evaluate, versatile, and easy to handle. Notwithstanding, the curse of dimensionality as well as the utility demands (e.g., so that the model covers sufficiently broad ranges of the system operating conditions), limit the applicability of conventional methods. A performance-driven modeling paradigm allows for mitigating these issue by focusing the surrogate setup process in a constrained domain encapsulating designs being of high quality w.r.t. the assumed figures of interest. The nested kriging framework capitalizing on this idea, renders the constrained surrogate using kriging interpolation, and has been shown to surpass traditional approaches. In pursuit of further accuracy improvements, this work incorporates the performance-driven concept into the fully-connected regression model (FRCM). The latter has been recently introduced in the context of frequency selective surfaces, and combined deep neural networks with Bayesian optimization, the latter employed to determine the network architecture and hyper-parameters. Using two examples of miniaturized microstrip couplers, our methodology is demonstrated to outperform both conventional modeling techniques and nested kriging, with reliable models constructed over multi-dimensional parameters spaces using just a few hundreds of samples.

G-SHAPED DEFECTED MICROSTRIP STRUCTURE BASED METHOD OF REDUCING CROSSTALK OF COUPLED MICROSTRIP LINES

G-SHAPED DEFECTED MICROSTRIP STRUCTURE BASED METHOD OF REDUCING CROSSTALK OF COUPLED MICROSTRIP LINES

Fast Design Closure of Compact Microwave Components by Means of Feature-Based Metamodels

Precise tuning of geometry parameters is an important consideration in the design of modern microwave passive components. It is mandatory due to limitations of theoretical design methods unable to quantify certain phenomena that are important for the operation and performance of the devices (e.g., strong cross-coupling effects in miniaturized layouts). Consequently, the initial designs obtained using analytical or equivalent network models require further adjustment. For reliability reasons, it has to be conducted using electromagnetic (EM) simulation tools, which entails considerable computational expenses whenever conventional numerical optimization algorithms are employed. Accelerating EM-driven design procedures is therefore highly desirable. This work discusses a surrogate-based algorithm for fast design closure and dimension scaling of miniaturized microwave passives. Our approach involves a small database of previously obtained designs as well as two metamodels, an inverse one, employed to yield a high-quality initial design, and the forward surrogate that provides predictions of the system sensitivities. The second model is constructed at the level of response features, which enables a more accurate gradient estimation and leads to improved reliability and a faster convergence of the optimization process. The presented technique is validated using two compact microstrip couplers and benchmarked against the state-of-the-art warm-start optimization frameworks.

Coupled microstrip slot resonators for bandstop filters: theory and design

Bandstop filters with single and dual stop-bands were implemented using coupled mode microstrip slot resonators (MSRs) for the first time. With compact and ease of fabrication, the MSRs provide excellent filter response as desired. It is found that the MSRs can offer narrow bandwidth of less than 20% fractional bandwidth and large isolation of more than 40 dB. The designs of MSRs and filters are systematically demonstrated with the method of coupled mode resonator theory. MSRs may be potential alternative for complicated and arbitrary design of BSFs to achieve desired frequency response.

Compact UWB Half-Mode SIW Bandpass Filter With Fully Reconfigurable Single and Dual Notched Bands

Compact ultra-wideband (UWB) bandpass filters based on the half-mode substrate integrated waveguide (SIW) with fully reconfigurable single and dual notched bands are proposed in this article. The lower stopband of the UWB bandpass filter is formed by the intrinsic cutoff frequency of the half-mode SIW, and transmission zeros in the upper stopband are created by utilizing three U-shaped slot resonators. Coupling microstrip resonators loaded by varactor diodes are placed along the open side of the half-mode SIW and microstrip feeding line to construct the in-band notches. By controlling the bias voltages and the size of resonators, fully reconfigurable single and dual notched bands can be obtained. Moreover, the frequency and bandwidth of each notched band can be controlled independently. To demonstrate the proposed technique, five and seven distributed coupling microstrip resonators are first applied to obtain the fully reconfigurable single notched band with the suppression level of 30 and 36 dB, respectively. Then, reconfigurable dual notched bands are demonstrated by changing the bias voltages using the same prototype with seven resonators. At last, nine resonant cells with two sets of different sizes are shown to design reconfigurable dual notched bands with frequency tuning range covering almost the full UWB passband.