Broadband Microstrip Research Articles

Design and Rapid Optimization Procedure of a Compact Broadband Microstrip Diplexer for VHF/UHF Band

ABSTRACTIn this paper, a design procedure of a compact broadband microstrip diplexer working on the Very High Frequency (VHF)/Ultrahigh Frequency (UHF) band is proposed. The diplexer consists of a fourth‐order Butterworth Low‐Pass Filter (LPF) and a sixth‐order elliptic High‐Pass Filter (HPF). The two filters are located on two substrates with a common ground. A microstrip‐to‐coaxial structure is utilized to transmit the power flow between the two substrates. For miniaturization, the utilized ideal capacitors and inductors are realized by the commercial lumped‐element capacitors and the curved microstrip line sections, respectively. All the middle design and rapid optimization processes from the schematic simulation by Advanced Design System (ADS) to the circuit simulation by CST STUDIO SUITE (CST) are given in the article. A prototype is fabricated and measured. The testing results are consistent with the simulation. The diplexer can operate at 225–775 and 880–2500 MHz. The insertion losses are 0.8 ± 0.3 and 0.9 ± 0.4 dB in the two working bandwidths. The isolation bandwidth of −20 dB level is as small as 105 MHz. The roll‐off is also sharp that the related bandwidths corresponding to the attenuation level −3 to −20d B are 90 and 30 MHz to the high and low bands, respectively. Besides, the return loss and isolation are larger than 10 and 20 dB approximately. The diplexer has a volume of 0.065 λg × 0.156 λg @775 MHz, which can be utilized to feed the miniaturized broadband VHF/UHF antenna system.

Advancements in Breast Cancer Detection through Broadband Microstrip Antenna Technology

Advancements in Breast Cancer Detection through Broadband Microstrip Antenna Technology

Methods for optimizing the characteristics of antenna elements and arrays simulating aggregative behavior and evolution of living be-ings in nature

Rigorous analytical solutions to antenna synthesis problems have been obtained for several of their simplest designs, while numerical solutions to specific versions of these problems in a strict electrodynamic formulation for the required practical structures take so much time in most cases that obtaining an optimal solution in an acceptable time is not always possible. For this reason, approximate methods for solving various technical problems, including antenna problems, based on significantly simpler operators than in electrodynamics have become widespread. This allows for a significant gain in time and optimal solutions to synthesis problems in a reasonable time by direct, targeted enumeration of the space of combinations of parameters characterizing the problem under consideration. If it is necessary to increase the accuracy of the solution obtained in this way, approximate methods allow one to select from a possible number of options a significantly smaller number with the best values of the objective function for subsequent analysis of these options by strict methods. A significant place among approximate optimization methods is occupied by evolutionary algorithms (EA), which have been developed since the second half of the last century. They imitate the behavior and evolution of various biological communities, generally obeying the theory of evolution and Darwin's natural selection. The article provides a brief overview of modifications of both well-known algorithms and the control parameters they contain: the genetic algorithm (GA), the method of swarm of biological entities (PSO), the method of differential evolution (DE), with the help of which a number of problems on the synthesis of antennas with discretely and continuously changing parameters have been solved, and a relatively new algorithm – the method of grey wolves (GWO). An example of implementation using the PSO/FDTD optimization algorithm of a dual-frequency and broadband microstrip antenna with an E-shaped plate has been given. A mathematical model and a block diagram of the modified IGWO algorithm have been presented. The superiority of its characteristics in terms of the accuracy of determining the global extremum and the speed of convergence over such well-known algorithms as GWO, SCA, SSA, PSO, FPA, MFO and BA has been shown based on testing these algorithms on twenty-three reference functions.

A novel 4 × 4 butler matrix with continuously tunable phase covering 360° range and application for 1‐D and 2‐D beam scanning array

AbstractA novel 4 × 4 Butler Matrix (BM) with continuously tunable phase covering phase range from −180° to 180° is proposed using substrate integrated waveguide technology. The proposed BM consists of two H‐plane hybrid couplers, two E‐plane hybrid couplers and four 180° tunable phase shifters. With this simple configuration, the proposed BM can realise a continuously tunable progressive phase difference from −180° to 180° in a one‐dimensional (1‐D) or two‐dimensional (2‐D) form. For demonstration, the proposed BM has been fabricated to feed a 1 × 4 or 2 × 2 broadband microstrip antenna arrays. The fabricated prototype has a 16.7% fractional impendence bandwidth centred at 6 GHz. The measured pattern for the 1‐D array showed a continuous beam scanning range from −39° to 39° in H‐Plane, while the measured radiation patterns for the 2‐D array showed continuous beam range from −27° to 30° in elevation and 0°–180° in azimuth. The measurement results were in good agreement with the simulation results.

A low‐profile wideband microstrip patch antenna using double half‐mode resonances

AbstractThis paper presents a miniaturized broadband microstrip patch antenna with a simple geometry. The radiation patch of this antenna comprises two rectangular patches with slightly different sizes, one side of each patch is grounded by metal via‐holes. Two rectangular patches are connected by a microstrip line and fed by a single port. Two rectangular patches produce two closely resonant frequencies achieving broadband performance. This antenna operates on the resonant method of short‐circuiting on one side. Metal via‐holes act as a short‐circuit wall allowing each patch to operate in TM0.5,0 mode. The size of a 1/4 wavelength resonant patch is only half of a conventional microstrip antenna, the overall size of this antenna is almost as same as a conventional rectangular microstrip antenna, making it compact in size. The wideband is achieved by combining two radiating patches, resulting in stable radiation and flat gain. Measurement results show that the antenna has an impedance bandwidth of 4.355.10 GHz (15.8%) using a common dielectric substrate without air layer thickness additionally. The maximum measured realized gain is 4.61 dB. This antenna has advantages of wide bandwidth, low profile, flat gain and ease of manufacturing.

A High-gain Low-sidelobe Dual-polarized Broadband Array Antenna

In this paper, we present a dual-polarized broadband low side lobe array designed for operation in the Ku-band. The antenna array operates within the frequency range of 14.0 GHz to 15.2 GHz, covering a bandwidth of over 8%. To realize this wide operational frequency, we have selected broadband microstrip antenna elements as the units of the array. In order to fulfill the demanding criteria of broadband performance and low sidelobe characteristics, we introduce a broadband low-sidelobe feeding network based on a directional coupler design. This feeding network ensures connectivity with the antenna units, resulting in a voltage standing wave ratio (VSWR) < 2 within the 14.0 GHz to 15.2 GHz frequency range. Furthermore, our antenna array achieves an array gain exceeding 21 dBi and keeps array sidelobes below -20 dB across the entire operating frequency band. Our research breakthrough addresses the critical design challenge of creating large-scale array antennas that combine broadband capabilities with high gain and minimal sidelobe interference.

A novel broadband and high-gain compact annular ring microstrip antenna for satellite applications

Abstract This article presents a novel compact design of an annular ring microstrip antenna (ARMSA), which has two stacked annular rings and is fabricated on a FR4 substrate for radar and satellite applications. The presence of different kinds of slots made the design of the recommended antenna very unique for Ku band applications. This novel compact structure of the antenna provided enhanced bandwidth and high gain. The suggested antenna works in Ku band and has 2.70 GHz bandwidth and 8.42 dB gain, which makes it suitable for satellite applications. The quality parameters of the proposed annular ring microstrip antenna have been compared with other existing annular ring microstrip antennas, which shows its efficient performance.

Broadband High Optical Transparent Intelligent Metasurface for Adaptive Electromagnetic Wave Manipulation.

Intelligent metasurfaces have garnered widespread attention owing to their properties of sensing electromagnetic (EM) environments and multifunctional adaptive EM wave manipulation. However, intelligent metasurfaces with broadband high optical transparency have not been studied to date, and most of the previous intelligent metasurfaces lack an integrated design for their actuators and sensors, resulting in lower integration levels. This study proposes a novel intelligent metasurface with adaptive EM wave manipulation ability and high optical transparency from visible to infrared bands. This metasurface consists of a transparent and current-controlled reconfigurable metasurface as an actuator by integrating patterned vanadium dioxide (VO2) into metal-meshed resonant units, transparent broadband microstrip antenna as a sensor, recognition-and-feedback module, and actuator- and sensor-integrated design on the same substrate. The EM-regulating capability of the designed transparent intelligent metasurface is theoretically analyzed using the coupled mode theory, and a prototype metasurface device is fabricated for experimental verification. Simulation and experimental results demonstrate that the metasurface exhibits over 80% normalized transmittance from 380 to 5,000 nm and adaptive EM wave manipulation (reflective strong shielding function with a shielding efficiency of over 24 dB, high transmittance function with a transmission loss of 1.24 dB, and strong absorption function with an absorption of 97%) according to the EM wave power parameters without manual intervention. This study provides an avenue for transparent intelligent metasurfaces with extensive application prospects in areas such as intelligent optical windows, radar enclosures, and communication.

A Diamond-type Broadband Microstrip Patch Antenna with a Folded Floor

A Diamond-type Broadband Microstrip Patch Antenna with a Folded Floor

Compact-size and Broadband Microstrip Patch U slot Antennas for C band Application and Stable Radiation Pattern overall band

A wide band antenna using U slot and truncated ground plane antenna is presented, The antenna used four U slot at the reflecting patch and via hole is shorted in between radiating and reflecting patch of an antenna, the antenna is all four corner truncated and four U shape is printed on ground plane. The proposed antenna is suitable for C band applications and stable radiation pattern to overall band. The antenna is resonance at a band of 7.1 to 14 GHz. The VSWR bandwidth of the proposed antenna is 65.40% and achieved a directivity of 6 dBi and gain 3.9 dBi. The size of the of the antenna is 18.18x15.541x1.5 mm3. The antenna is suitable for Wimax, WLAN and other C band applications.

Optimization of Broadband Microstrip Antenna Device for 5G Wireless Communication Systems

Abstract The paper proposes a new method for finding the optimal design of complementary split ring resonator cells for a microstrip antenna, which makes it possible to purposefully optimize the parameters of resonator cells, which significantly improve the electrical characteristics of the antenna. This antenna is designed for cellular communication 5G. The proposed method combines a regression model using a deep network based on fully connected neural layers with a search based on the conditional optimization algorithm COBYLA to find the optimal design parameters of resonator cells. This approach fully automates the process of creating microstrip antennas with resonator cells based on metamaterials and makes it possible to find the parameters of complementary split ring resonator cells that provide the optimal operating mode as a whole and gives the maximum level of antenna radiation while maintaining the bandwidth. The small size of complementary split ring resonator cells opens up the possibility of using this peculiar configuration to create compact and efficient microstrip antennas.

6G Broadband and High Directive Microstrip Antenna with SIW and FSSs

Sixth-Generation (6G) wireless communication networks require the fabrication of broadband and high directivity microstrip antennas to offset the high atmospheric path loss beyond 100 Gigahertz (GHz). In this paper, we designed and proposed a couple of high-gain and broadband microstrip array antennas that have been designed within a Finite Integration Technique (FIT) solver at Computer Simulation Technology Microwave Studio (CST MWS) software in a series-parallel feeding method for a resonance frequency above 107 GHz. A Substrate-Integrated Waveguide (SIW) with dual outputs has been used at these antennas and with WR-08 waveguide that covers the 90-140 GHz frequency range, while the first was without Frequency Selective Surfaces (FSSs), and the second was with the FSSs to increase the antenna directivity further. The first design was simulated with a Finite Element Method (FEM) solver at Ansys High-Frequency Structure Simulator (HFSS) to compare the simulation results of this antenna. This comparison's peak gain and Bandwidth (BW) were correspondingly 25.3 dB, 12.5 GHz, 23.1 dB, and 11 GHz from the Ansys HFSS and the CST MWS. Thus, the accuracy and the slight deviation of the compared simulation results from each other validated the offered 6G antenna designs. Therefore, after experimental verification, the proposed antennas can be employed in 6G future wireless communication networks.

Globalized Knowledge-Based, Simulation-Driven Antenna Miniaturization Using Domain-Confined Surrogates and Dimensionality Reduction

The design of contemporary antenna systems encounters multifold challenges, one of which is a limited size. Compact antennas are indispensable for new fields of application such as the Internet of Things or 5G/6G mobile communication. Still, miniaturization generally undermines electrical and field performance. When attempted using numerical optimization, it turns into a constrained problem with costly constraints requiring electromagnetic (EM) simulations. At the same time, due to the parameter redundancy of compact antennas, size reduction poses a multimodal task. In particular, the achievable miniaturization rate heavily depends on the starting point, while identifying a suitable starting point is a challenge on its own. These issues indicate that miniaturization should be addressed using global optimization methods. Unfortunately, the most popular nature-inspired algorithms cannot be applied for solving size reduction tasks because of their inferior computational efficacy and difficulties in handling constraints. This work proposes a novel methodology for the globalized size reduction of antenna structures. Our methodology is a multi-stage knowledge-based procedure, initialized with the detection of the approximate location of the feasible region boundary, followed by the construction of a dimensionality-reduced metamodel and global optimization thereof; the last stage is the miniaturization-oriented local refinement of geometry parameters. For cost reduction, the first stages of the procedure are realized with the use of a low-fidelity EM antenna model. Our approach is verified using four broadband microstrip antennas and benchmarked against multi-start local search as well as nature-inspired methods. Superior size reduction rates are demonstrated for all considered cases while maintaining reasonably low computational costs.

Low‐profile and broadband microstrip antenna with pattern diversity

AbstractThis paper presents a low‐profile and broadband pattern diversity microstrip antenna with quasiperiodic radiating patches fed by two slots. The thickness of the whole design is only 0.044λ0 (λ0 is the free‐space wavelength of the center frequency), showing great potential in applications. The broadband property is realized by efficiently exciting TM10 mode and antiphase TM20 mode and forming two resonant frequencies in the target band. The antenna can generate a broadside or difference pattern by switching the input port of the broadband 180° hybrid coupling feed network. The measured results show that the coincident impedance bandwidth of the antenna working in the two pattern modes is 20.5% (3.20–3.93 GHz), and the maximum gain values are 6.85 dBi for the directional pattern and 5.80 dBi for the difference pattern.

Compact Tunable Broadband Filtering Attenuator Based on Variable Resistors

In this letter, a compact microstrip broadband filtering attenuator based on variable resistors is proposed with high-frequency selectivity. It can achieve tunable attenuation characteristics over a broad frequency band by changing the resistance of the variable resistors. Due to the symmetry of the circuit structure, it is analyzed using odd-and even-mode methods. For demonstration, a filtering attenuator prototype is fabricated and measured, which operates from 1.3 to 2.8 GHz and realizes tunable attenuation from 3.26 to 15.61 dB. The results of theoretical calculations, simulations, and measurements agree well with each other, which validates the feasibility of the proposed design.

A wideband monopolar patch antenna with a high system fidelity factor for IR‐UWB application

AbstractA compact, broadband microstrip patch antenna with stable monopole‐like radiation patterns is proposed for impulse‐radio ultrawideband (IR‐UWB) positioning systems. Such the antenna consists of a circular patch with eight conductive vias placed concentrically, resulting in the and modes. Moreover, a tapered feeding probe at its center is presented to enhance the matching and excite an antiresonance mode. The compact size of is obtained by using a square ground. The measured results show that the antenna has an impedance bandwidth of 44.1% from 6 to 9.4 GHz and stable monopole‐like radiation patterns in the frequency domain. Finally, a system fidelity factor larger than 96% and a relatively stable group delay are simulated and measured in the time domain. Therefore, this antenna can be potentially useful for UWB pulse transmission with attractive features in engineering applications.

Broadband Flexible Microstrip Antenna Array with Conformal Load-Bearing Structure.

To enhance the load-bearing mechanical properties and broadband electromagnetic characteristics of the conformal antenna, a broadband microstrip antenna array with a conformal load-bearing structure is proposed in this paper, which consists of three flexible substrate layers and two honeycomb core layers stacked on each other. By combining the antenna and honeycomb core layer in a structural perspective, the antenna array is implemented in the composition function of surface conformability and load-bearing. Additionally, the sidelobe level of the antenna is suppressed based on the reflection surface loaded. Meanwhile, an equivalent model of a honeycomb core layer has been established and applied in the design of a conformal antenna with a load-bearing structure. The presented model increases the accuracy of simulated results and reduces the memory consumption and time of the simulation. The overall size of the proposed antenna array is 32.84 × 36.65 × 4.9 mm (1.36 λ0 × 1.52 λ0 × 0.2 λ0, λ0 is the wavelength at 12.5 GHz). The proposed antenna element and array have been fabricated and measured in the flat state and under other various bending states. Experiment results show the operating relative bandwidth of the antenna array is 20.68% (11.67-13.76 GHz and 14.33-14,83 GHz) in the flat state. Under different bending conditions, the proposed antenna array covers 24.16% (11.08-14.1 GHz), 23.82% (10.63-13.5 GHz), and 23.12% with 30°, 60°, and 90° in the xoz plane (11.55-14.33 GHz). In terms of mechanical load bearing, the structure has better performance than the traditional single-layer honeycomb core load-bearing structure antenna.

Design of broadband microstrip three‐way directional coupler for multibeam antenna application

AbstractIn this letter, a design of broadband microstrip three‐way directional coupler (TWDC) is presented. The broadband performance of the microstrip TWDC is realized by the method of cascading multi‐section. The broadband TWDC is designed to achieve equal power division and −120°, 0°, and +120° phase differences between output signals. To verify the broadband design, a prototype of three‐section microstrip TWDC operating at C‐band is designed, fabricated and measured. The measured results show that the power division error of the designed broadband TWDC is less than ±0.7 dB and phase error is less than ±12° at a relative bandwidth of 16%. To verify its performance in multibeam application, the designed TWDC is used as a beamforming network for multibeam antenna array to generate three orthogonal beams.

Method for measuring magnetic susceptibility of magnetic nanoparticles up to millimeter-wave frequency range

A novel method for measuring the complex magnetic susceptibility of magnetic nanoparticles (MNPs) has been developed by a broadband microstrip line-type probe with a frequency range of up to 50 GHz. Two external orthogonal DC fields, Hhard and Heasy, were applied to change the susceptibility of MNPs (Streptavidin coated, 200 nmϕ, number of MNPs about 1010) based on magnetization switching theory. The susceptibility of MNPs in the liquid, solid state, and after biotin-avidin reaction with polymer beads (2 μmϕ, number of polymer beads about 108) was evaluated. A clear FMR frequency of MNPs and the same FMR frequency shift trend as Hhard changed was observed around 2–10 GHz in both liquid and solid states. The susceptibility of MNPs reached maximum when Hhard was 0.1 T which is approximately equal to Heasy (0.135 T). The maximum values of real and imaginary parts increased by a factor of 3.39 and 1.66 compared to when Hhard was 0. The obtained results indicate that the magnetic anisotropy was successfully controlled in the liquid and solid states of MNPs aggregate. Furthermore, after the biotin-avidin reaction of MNPs with polymer beads, the imaginary part of susceptibility showed a decreasing trend regardless of the increase in Hhard, and its half-width expanded by 35.1% at maximum when Hhard was 0.15 T.

Compact, Broadband and High Gain Uniplanar Quasi-Yagi Microstrip Antenna for End-Fire Radiation

This paper describes a uniplanar, compact, broadband, and high gain quasi-Yagi microstrip antenna to achieve radiation in the end-fire direction. The major elements of the proposed antenna include one element of each: reflector, ground plane (acts as another reflector), driven, and director. The concept of microstrip and Yagi-Uda antennas are coupled to lower the inter-element spacing, thus reducing the antenna dimensions along the boom length significantly. U-shaped reflector elements are used to reduce the lateral dimension of the antenna. The antenna's directivity is enhanced in the lower and upper-frequency bands with the help of reflectors and directors, respectively. A compact size of (0.52 × 0.22 × 0.009) has been achieved along with an impedance bandwidth of 46.5% for |S 11| < −10 dB and a peak gain of 6 dBi (with 1 dB variations) over the entire bandwidth. The novelty of the proposed uniplanar quasi-yagi MSA is proved by comparing the Figure of Merit (FoM) with the reported work. The proposed antenna is fabricated, and the measured results are in good agreement with the simulated results. The proposed uniplanar quasi-Yagi antenna is ideal for wireless applications that required end-fire radiation in 2G, 3G, 4G, Wi-Fi frequency bands, and portable direction-finding devices.