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Compact Antennas with Pattern Diversity
Published in Shiban Kishen Koul, G. S. Karthikeya, Millimetre Wave Antennas for 5G Mobile Terminals and Base Stations, 2020
Shiban Kishen Koul, G. S. Karthikeya
It is observed that when the dipole is below 3 mm, the antenna has a poor impedance match and over 5 mm creates an over-moded antenna for the designed feedline and transformer. If the transformer is redesigned, then the corresponding feeding structure also has to be modified to match the impedance with the radiator. Hence, 4.2 mm is chosen as the length of the dipole arm, whose |S11| is shown in Figure 4.2. The simulations were performed using the industry standard Ansys HFSS. A perfect electric conductor bridge was used for CPW feeding in the simulation. A test simulation with the connector design was also performed, to illustrate the effects of the connector on the antenna. The reflection coefficient was almost invariant, both with and without the connector, but the simulation time increased phenomenally because of the composite structure of electrically large metal with a reasonable electrical size of the antenna. The 10 dB bandwidth is from 24 to 30 GHz. The return loss characteristics are maintained even with a CPW feedline gap of up to 350 μm. Tapered lines and quarter-wave transformers would lead to a relatively narrow band because of the frequency sensitive input impedance at the balanced CPS line of the folded dipole. A 20% wide impedance bandwidth for a mobile terminal is justified to accommodate future 5G bands near 28 GHz; this is a valid design strategy even for existing 4G commercial smartphones. The integrated antenna of the mobile terminal must be able to operate independently of the operator and the geography. The slight frequency detuning of the measured curve could be attributed to the fabrication tolerances, frequency sensitive variation of the dielectric constant, and the alignment with the end-launch connector.
Design and Measurements Process of Wearable Communication, Medical and IOT Systems
Published in Albert Sabban, Wearable Systems and Antennas Technologies for 5G, IOT and Medical Systems, 2020
Ansys HFSS is a three-dimensional (3D) EM simulation software for designing and simulating high-frequency devices, such as antennas, antenna arrays, RF and microwave components, high-speed interconnects, filters, connectors, integrated circuits (ICs) packages and printed circuit boards (PCBs). Ansys HFSS is employed to design high-frequency, high-speed communications systems, radar systems, RF components and modules, satellites, Internet of Things (IOT) products and other high-speed RF and digital devices. For more information see, https://www.ansys.com/products/electronics/ansys-hfss.
Compact ultrawideband filter with reconfigurable band notch characteristics
Published in International Journal of Electronics Letters, 2023
Dharmendra Kumar Jhariya, Akhilesh Mohan
The proposed compact UWB filter is shown in Figure 1(a). It is designed on the RT/Duroid 3010 substrate having dielectric constant εr = 10.2, tanδ = 0.0035 and thickness h = 0.635 mm. A stepped impedance slotline resonator (SISR) is etched at the bottom side of the substrate. Whereas, on the top side of the substrate, two parallel open circuited microstrip lines of dimensions 12.5 mm × 10 mm are coupled to the SISR. These two open circuited microstrip lines, separated by a distance d, are connected to 50 Ω input/output feed lines with a width of W0. In order to investigate the performance of the proposed design, EM simulations are performed using Ansys HFSS. Figure 1(b) shows the simulated S-parameters of the proposed UWB filter. The optimised design parameters of UWB filter are (all are in mm): S = 1, L = 5, L1 = 2.5, W1 = 0.5, L2 = 5, W2 = 2.4, L3 = 5, L4 = 4, W4 = 1, S1 = 1, W0 = 0.57, g = 0.2, d = 0.25.
Broadband Multi-Stub PCB Monopole Antenna
Published in IETE Journal of Education, 2022
Figure 7 depicts the radiation pattern of the PCB monopole antenna at 2450 MHz. Figures 8 and 9 depict the radiation patterns of the proposed double stub and triple stub PCB monopole antennas, respectively. The radiation pattern is observed to be consistent over the entire bandwidth, where the gain variation is within 0.5 dB (radiated power variation < 10%). ANSYS HFSS is used for 3D Electro-Magnetic simulation [16].
Dielectric Free Wide Scan UWB Low Cross-Pol Metallic Vivaldi Antenna for Active Phased Array Radars
Published in IETE Journal of Research, 2022
The design of MVA is carried out in two steps; (a) under isolated condition (no nearby elements) and (b) under array environment (assuming an infinite array). The design is carried out using the Floquet model-based approach in Ansys HFSS. Figure 1(a) shows the proposed geometry of MVA structure with an exponential taper. MVA has an overall dimension of 21 mm (L) × 16 mm (W), which indicates a smaller profile as compared to similar MVA structures (see Table 1 for comparison) presented in the literature. MVA’s structure design can be broadly divided into two parts: the exponential flare (with flaring rate, R) and the feeding mechanism. Assuming the antenna is placed in the xy-plane and its axis aligned with the y-axis of the coordinate system, the exponential flare (or taper profile) can be defined by the opening rate, R and two points P1(x1, y1) and P2(x2, y2) (see Figure 1(a)) given as [18,23]: where MVA designed is approximately 0.4λ thick, 1.3λ long and 1λ wide. The width of the fins is approximately 0.5λ. The complete dimensions are illustrated in Figure 1(a). The thickness of MVA as mentioned was chosen to allow sufficient space for drilling a through hole equal to the radii of the coax probe. In addition, the thickness of MVA reduces the gap between rows of the antenna arrays, thereby eliminating the gap–resonances [16]. A 50Ω standard SMA connector is simply inserted, pressed and bolted in its place through a 0.162″ diameter hole drilled in the rear side of thick MTSA (see Figure 1(b) and Figure 5(a)). This removes the need of any soldering of the contacts. In the simulation, coax-to-slot transition was optimized along with the model of SMA connector for over the BW. Since antenna is fed directly from the rear side by SMA coax, slot stub was bent and turned orthogonally w.r.t. the flared slot line to avoid any interference with the feed pin (see Figure 1(b)). The slot line shape and the slot stub dimensions have been optimized to cancel the cross-polarization interference occurring from the field asymmetries thus introduced. The resultant surface current distribution is shown in Figure 1(b) simulated using HFSS. Table 1 illustrates the miniaturization of the proposed MVA geometry achieved w.r.t. the similar geometries in the literature.