Minimum Return Loss Research Articles

Impact of Feed Point Position on Patch Antenna’s Return Loss and Bandwidth for UWB Applications

The demand for compact, lightweight, and high-performance antennas has increased in recent times in the communication industry. Microstrip patch antenna (MPA) becomes a better choice to effectively fulfill these requirements. In this study, hybrid techniques of partial ground plane, slotted patch, and defective ground structure are employed in MPA design to reduce the return loss, good impedance matching, and increased the bandwidth, gain, and efficiency of the antenna. This research demonstrates the impact of altering the feed point position, a crucial phenomenon of antenna design, on the patch antenna and determines the proper feed point location by comparing a minimum return loss (S11) which achieves the highest performance for the designed antenna. High-frequency structure simulator (HFSS) software is used to design and simulate the patch antenna. The operating frequency of the antenna is 6.85 GHz for UWB applications (3.1–10.6 GHz). A FR4 epoxy substrate material with dimensions of 30 mm × 20 mm is used to design the antenna. It has a dielectric constant of 4.4, a thickness of 0.8 mm and a tangent loss of 0.02. Multiple resonant frequencies are observed with different return losses for each feed location. The analysis shows that the finest feeding point is found at the center of the patch (9, 0) with a very low return loss (-28.35 dB), and a high impedance bandwidth (19.7 GHz). The antenna also achieved a gain of 4.46 dB, a directivity of 4.6904 dB, and a radiation efficiency of 95.90%. Hence, the location of the feed point can be considered as an influential factor in the antenna design.

Uji DESAIN DAN SIMULASI ANTENA MIKROSTRIP PATCH PERSEGI DENGAN METODE PENGUMPANAN INSET-FED UNTUK APLIKASI S-BAND

This research is to find out that the microstrip antenna is one of the most widely applied antennas for various radio applications because of its low profile and high performance. This paper discusses design and simulation of the rectangular patch microstrip antenna (RPMA) for S-band radio by using inset feeding. Initially, theoretical calculation was performed, followed by performance evaluation by using AWR simulator. Inset deep iterations were conducted through repeated simulation adjustment to obtain optimal design. Based on the concluded simulation adjustment, the minimum achieved VSWR is 1.056 to get bandwidth of 104.5 MHz (3.1636 3.2681 GHz). The minimum return loss that can be achieved is -31.33 dB with gain of 5.777 dB.

Development of Split Ring Resonator Shaped Six Element 2 × 3 Multiple Input Multiple Output Antenna for the C/X/Ku/K Band Applications

In this manuscript, we have numerically investigated and experimentally verified the six-element split ring resonator and circular patch-shaped multiple input, multiple output antenna operating in the 1–25 GHz band. MIMO antennas are analyzed in terms of several physical parameters, such as reflectance, gain, directivity, VSWR, and electric field distribution. The parameters of the MIMO antenna, for instance, the envelope correlation coefficient (ECC), channel capacity loss (CCL), the total active reflection coefficient (TARC), directivity gain (DG), and mean effective gain (MEG), are also investigated for identification of a suitable range of these parameters for multichannel transmission capacity. Ultrawideband operation at 10.83 GHz is possible for the theoretically designed and practically executed antenna with the return loss and gain values of −19 dB and −28 dBi, respectively. Overall, the antenna offers minimum return loss values of −32.74 dB for the operating band of 1.92 to 9.81 GHz with a bandwidth of 6.89 GHz. The antennas are also investigated in terms of a continuous ground patch and a scattered rectangular patch. The proposed results are highly applicable for the ultrawideband operating MIMO antenna application in satellite communication with C/X/Ku/K bands.

Design and implementation of wideband terahertz on-chip antenna for terahertz frequency application

Microstrip antenna have been adaptable because of their appealing features such as low profile, low weight, and low cost, microstrip antennas have been widely used in modern wireless communication, satellite communication, 2G/3G mobile services, marine or land vehicle navigations (GPS), wireless LAN access, and many small devices embedded with Bluetooth, UWB, Zigbee, DVB, and so on. Confirmability, as well as compatibility with MMIC designs. This paper presented a multi-band antenna for multifunctional wireless message employing a defective ground plane. The antenna is employed in twelve slots in a ground plane, and they function as electronics band gap tuning, allowing us to tune the frequency for a variety of wireless communication applications. The suggested design operates in four bands: 4.6 GHz to 5 GHz, 5.2 GHz to 5.5 GHz, and 5.6 to 6.2 GHz.and 6.5 to 8.9 GHz. The exciting patch, also known as a radiator patch, is made up of a parasitic and rectangular slot, as well as a segregated ground and exciting patch that runs through a FR4 dielectric substrate. The radiation patch and ground are linked by a 0.5 mm hole. A design's structure is concise and straightforward. A proposed antenna has dimensions of 20*24*1.5 mm3 with regard to wavelength 0.30, where 0 is a free space wavelength. The proposed design is appropriate for numerous wireless communication protocols, including WLAN, WiMAX, and X band applications. A proposed antenna has a bandwidth of 61%, a VSWR of 2, a minimum return loss of −20dBi, and a directivity of 7dBi.

Yttrium-substituted Co0.5Ni0.5YxFe2-xO4 ferrites as microwave absorbers by investigating structural, magnetic, dielectric, and absorption characteristics

The effect of Yttrium Substitution on Co0.5Ni0.5YxFe2- xO4 (0.0 ≤ x ≤ 1.0) Ferrites as Microwave Absorbers was investigated to include structural, magnetic, dielectric and X-band absorption properties. The main objective of this work is to enhance microwave absorption properties of materials with interesting dielectric/magnetic behaviors by doping rare earth element of Yttrium based on transition metals. The hydrothermal method was used to create Yttrium (Y) substituted nanoparticles, and the effects of Y-ion substitution on the characteristics, structural, magnetic features were examined by XRD, FT-IR, SEM-EDS, TEM-SAED, and VSM, respectively. Electromagnetic properties were obtained from microwave scattering parameters measured via a metal-backed transmission line and Nicholson-Ross Weir techniques using a vector network analyzer (VNA) in conjunction with an X-band waveguide set. Return loss (RL) values of the samples were obtained from the electromagnetic constitutive parameters (permittivity and permeability). According to the XRD measurements, hexagonal crystal structure of ferrite and YFeO3 as secondary phase nanocrystal sizes are between 11 and 67 nm. Refined structural parameters using Rietveld analysis are carried out using the TOPAS refinement program. A good match was observed between the diffraction patterns obtained and calculated by Rietveld analysis. Moreover, the morphological analyses indicate that the relatively small spherical structures of Ni-Co ferrites particles can be seen to change from spherical to hexagonal-shaped with increasing yttrium concentration. The results of the FT-IR study show that the spinel structure has formed as predicted because the expected range of absorption bands is present. According to magnetic measurements, the coercivity (Hc) results show a modest increase in porosity as the Y-content rises. The results revealed that the minimum RL value and bandwidth vary significantly with the amount of Yttrium in the mixture, indicating that the obtained structures will be useful for broadband microwave applications.

Performance Simulation and Fused Filament Fabrication Modeling of the Wave-Absorbing Structure of Conductive Multi-Walled Carbon Nanotube/Polyamide 12 Composite.

Fused filament fabrication (FFF) is a reliable method for fabricating structured electromagnetic wave (EMW) absorbers from absorbing materials. In this study, polymer-matrix composites were prepared using polyamide 12 (PA12) which was recovered from selective laser sintering (SLS) as the substrate and multi-walled carbon nanotubes (MWCNT) as the filler. The CST software is used for simulation calculation and study of electromagnetic wave absorption characteristics of composite materials. After that, based on the obtained parameters and results, modeling was carried out, and finally, EMW absorbers with various microstructures were fabricated by FFF. For the honeycomb structure sample, when the side length is 5 mm and the height is 2 mm, the minimum return loss (RL) of the composite at 15.81 GHz is -14.69 dB, and the maximum effective absorption bandwidth is 1.93 GHz. These values are consistent with the simulation results. The pyramid structure has better absorbing performance than plate structure and honeycomb structure. According to simulation calculations, the pyramid structure shows the best performance at an angle of 28°. The absorption performance of the printed pyramid structure sections exceeded the simulated values, with effective absorption bandwidth (EAB) reaching all frequencies from 2 to 18 GHz, with a minimum return loss of -47.22 dB at 8.24 GHz.

Superlative split ring resonator shaped ultrawideband and high gain 1×2 MIMO antenna for Terahertz communication

The manuscript represents miniaturized two-radiating element-based MIMO antennas for the frequency span of 1 THz to 20 THz. Five MIMO antenna structures are designed and analysed by modifying the shape of radiating elements and ground regions to attain better performance. The proposed structures’ performance is compared in terms of return loss, isolation, total gain, directivity, radiation pattern, directivity, peak gain, ECC, TARC, CCL, and TARC. The presented design provides the minimum return loss of −50.85 dB, maximum isolation of 38 dB, maximum bandwidth (S11< −10 dB) of 6.99 THz, maximum normalized directivity of 75°, and peak directivity of 4.635 dB. In addition, the other MIMO performance characteristics, such as the Diversity Gain (DG), Envelop Correlation Coefficient (ECC), Channel Capacity Loss (CCL), and Total Active Reflection Coefficient (TARC) are all within acceptable range. Finally, the presented design is compared with other relevant designs, and a good performance is observed. The proposed structure provides the solution for a superlative MIMO antenna with ultra-wideband, high gain, and compact structure. The proposed design is used for the B5G, THz wave radar, vehicular communications, astronomical radiometric applications imaging, health care, sensing, screening for weapons, explosives, and biohazards identification.

Liquid Based Wideband and Switchable 3-D Frequency-Selective Rasorber

A switchable 3-D frequency selective rasorber (FSR) with wide absorption bands and without lumped components or commercial magnetic absorbers is presented. The absorption path is constructed by embedding a hybrid liquid microwave absorber inside a parallel plate waveguide to create an extra-wide absorption band. A reflection layer based on water is placed behind the FSR to realize the reconstruction from FSR to a band-notched absorber (BNA) by controlling the presence or absence of water. The liquid-based absorber is analyzed by a multimode dielectric resonant circuit, and the fundamental operating principle of the FSR is demonstrated with the help of an equivalent circuit model. A prototype is designed, fabricated, and measured and exhibits a passband at 5.10 GHz with a transmission bandwidth of 18.5% for less than 3 dB insertion loss and a fractional bandwidth of 146.8% with reflectivity less than −10 dB in the FSR mode. In the BNA mode, it has a minimum return loss of 0.72 dB and a good absorption band from 2.5 to 4.6 GHz and from 5.7 to 16.5 GHz. This switchable FSR may be used in an antenna system to decrease out-of-band reduce radar cross section while also functionally enabling switching between the radome and the antenna reflector.

A Balanced Substrate Integrated Waveguide Phase Shifter with Wideband Common-Mode Suppression

In this paper, a slotted substrate integrated waveguide (SIW) is used to create a balanced phase shifter with wideband common-mode (CM) suppression. Differential-mode (DM) impedance matching and CM suppression are achieved by utilizing the fact that TE20 mode and TE10 (TE30) mode can only transmit DM signals and CM signals, respectively, and by increasing the bandwidth for CM suppression via slots. Furthermore, a wideband phase shift with low phase deviation can be obtained due to the phase slop counteract between the slot and the delay line. Compared with the state-of-the-art, the proposed one has the advantages of wideband CM suppression, wide phase shift range, and a simple and easy-to-make structure. Five prototypes covering the frequency of 3.5 GHz are designed with the relative operating bandwidth for 45° ± 2° (90° ± 4.5°, 135° ± 6°, and 180° ± 8°) phase shifter of 20% (20%, 20%, and 20%), with the minimum insertion loss of 0.41 dB (0.5 dB, 0.58 dB, and 0.59 dB), with the minimum return loss greater than 15 dB, and with the relative bandwidth for 15-dB CM suppression of 59% (59%, 58%, and 57%).

Simulation and design of the circular polarization microstrip antenna with CSRR metamaterial structure

This paper has discussed the design of a circular polarized microstrip single patch antenna using a complementary split-ring resonator (CSRR) placed in the patch section. The design used an epoxy FR4 substrate with a thickness of 1.6 mm. Antenna specifications that resonate at a frequency of 1.57 GHz are very supportive for GPS applications. The design is carried out with the AWR simulator. The implementation of CSSR metamaterial structure in the patch was successful in improving the design performance compared to the design without using CSRR. Based on the simulation results, the minimum return loss is -40.92 dB at a frequency of 1.57 GHz and an axial ratio below 3 is achieved for the frequency range of 1.56 – 1.59 GHz. Reduction of substrate and patch dimensions was achieved by 36.5% and 46.9%, respectively.

Size reduction of the square microstrip patch antenna with Koch fractal for 1.575 GHz applications

This paper discusses a square patch microstrip antenna with a resonant frequency of 1.575 GHz. The initial design of the antenna was carried out using a theoretical approach and then applied fractal Koch with 1-iteration and 2-iteration. The design optimization is done using the AWR simulator. Based on the optimal design results, the use of Koch fractals has been able to reduce the antenna size. In the first iteration, the antenna size can be reduced by 28% with a minimum return loss value of -33.36 dB at a frequency of 1.575 GHz. In the second iteration, the antenna size can be reduced by 42.4% from the design without fractals with a minimum return loss of -37.18 dB at a frequency of 1.575 GHz. The gain of each antenna design has almost the same value, namely 5.115 dB.

A 4th-Order LTCC Bandpass Filter with Both Tunable Center Frequency and Bandwidth

Reconfigurable filters are one of the key components in microwave communication systems. This letter presents a 4th-order low-temperature cofired ceramic (LTCC) bandpass filter with both a tunable center frequency and bandwidth. This filter has four resonators, and each resonator consists of a circular patch, a center-through via, and two varactors. The varactors are placed on the top and bottom layers of the ceramic medium, which can effectively reduce the size of the 4th-order tunable filter. Three transmission zeros (TZs) are introduced to improve the upper stopband rejection. This filter demonstrates a 3-dB bandwidth (BW) range of 170–220 MHz around 2.86 GHz and a 3-dB BW range of 190–320 MHz around 3.2 GHz with a 13 dB minimum return loss. Insertion loss ranging from 3.5 dB to 6.85 dB has been obtained. The overall circuit size, including the package, is 11 mm × 6 mm × 1.6 mm.

A C‐band 370 W MMIC high‐power PIN limiter with heterogeneous integration

AbstractThis paper designs a mesa‐structured monolithic microwave integrated circuit (MMIC) limiter working in C‐band. The quasi‐vertical Si‐based PIN diodes are heterogeneously integrated on the SiC substrate with high thermal conductivity, such that the parasitic parameters are greatly reduced and the power capacity is enhanced. According to the measured results, a maximum insertion loss of 1.1 dB and a minimum return loss of 17.69 dB for both input and output terminals are realized to cover the 5–6 GHz frequency range. The flat leakage of 23 dBm is achieved for a 150 W continuous wave and 370 W pulse input signal level. We believe the proposed MMIC limiter provides an effective tool that can be used in the transmit‐receive modules working in C‐band.

Millimeter-Wave Broadband Waveguide-to- Microstrip Transition Using a Bifurcated Probe

In this letter, a novel waveguide-to-microstrip vertical transition using a bifurcated probe is presented. The bifurcated probe consists of a pair of thin parallel <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$E$ </tex-math></inline-formula> -plane probes and bend branches, which forms a strong current crowding effect for electromagnetic energy coupling from rectangular waveguide and broadband impendence matching. Therefore, the bifurcated probe can effectively reduce the sensitivity of probe dimensions to transition performance and design difficulty. To demonstrate this concept, a back-to-back bifurcated probe transition operating at WR-4.3 band (170–260 GHz) was fabricated and measured. Measured results show the double transition covers the entire WR-4.3 band with a minimum return loss (RL) of 16 dB and an average insertion loss (IL) of 0.84 dB, respectively.

Design and Analysis of Step Sized Substrate Integrated Waveguide and Antenna

In this article, a step-sized Substrate Integrated Waveguide (SIW) is designed, simulated, and a prototype is developed for performance validation. The various parameters of the SIW, like propagation constants, modal field distribution, etc., are analyzed and investigated. An antenna is designed and developed using the proposed SIW. The various important parameters of the designed stepped SIW antenna, such as return loss, total antenna gain, radiation pattern, radiation efficiency, etc., are determined and validated through experimental standers. The antenna is simulated using a commercially available finite element method-based high frequency structural simulator. The designed antenna shows the wideband frequency response from 6 GHz to 22 GHz in the simulating frequency range. The designed structure shows the various resonant frequencies. A minimum return loss of -39 dB is achieved at a frequency of 17 GHz. Overall, the gain of the antenna is high. The total maximum gain achieved by this antenna is around 12.5 dBi. The developed antenna offers high efficiency on the FR4 substrate.

Substrate Integrated Waveguide Quasi-Elliptic Filter with Arbitrary Termination Impedances

This paper presents a quasi-elliptic filter (QEF) with arbitrary termination impedances (ATI). The proposed QEF is designed by adding cross-coupling between the first and last resonators of an ATI bandpass filter (BPF) with the Chebyshev response. The proposed QEFs with ATI can be designed in even-order resonators and the location of the pair transmission zeros (TZs) is controllable. To prove the validity of the proposed design, the fourth-order QEFs with ATI were implemented on a single-layer substrate-integrated waveguide (SIW) cavity at a center frequency (&lt;i&gt;f&lt;/i&gt;&lt;sub&gt;0&lt;/sub&gt;) of 10 GHz with the pair TZs at 10 ± 1.4 GHz. These SIW QEFs with ATI improve frequency selectivity and effectively suppress the out-of-band signal with high power handling. The measured maximum insertion loss (|&lt;i&gt;S&lt;/i&gt;&lt;sub&gt;21&lt;/sub&gt;|) and minimum return loss (|&lt;i&gt;S&lt;/i&gt;&lt;sub&gt;11&lt;/sub&gt;|) of the SIW QEF with unequal real-to-real ATI are 0.93 dB and 17.4 dB, respectively, in the passband. Similarly, the maximum |&lt;i&gt;S&lt;/i&gt;&lt;sub&gt;21&lt;/sub&gt;| and minimum |S&lt;i&gt;S&lt;/i&gt;&lt;sub&gt;11&lt;/sub&gt;| of the SIW QEF with complex-to-real ATI are 1.2 dB and 18 dB, respectively.yer substrate-integrated waveguide (SIW) cavity at a center frequency (

An On-Chip Planar Inverted-F Antenna at 38 GHz for 5G Communication Applications

This paper presents an on-chip planar inverted-F antenna (PIFA) implemented in TSMC 180 nm CMOS process technology. The antenna operates at a 5 G millimeter-wave center frequency of 38 GHz. The ultrathick metal (UTM) layer of the technology is utilized to implement the on-chip antenna (OCA). The OCA is positioned close to the edge of the microchip for improving the gain performance of the antenna. The open end of the antenna is folded to develop a top-loaded PIFA structure yielding better 50 Ω impedance matching and wider bandwidth. On-wafer measurements are conducted through the Cascade Microtech Summit 11K probe-station and ZVA-50 vector network analyzer to measure the return loss and gain of the fabricated on-chip antenna. The measurements are performed after placing the fabricated OCA over a 3D-printed plastic slab to minimize the reflections from the metallic chuck of the probe station. The measurement results show that the fabricated on-chip PIFA achieves a minimum return loss of 14.8 dB and a gain of 0.7 dBi at the center frequency of 38 GHz. To the best of the authors’ knowledge, the presented OCA is the first on-chip PIFA designed, fabricated, and tested at the 5G millimeter-wave frequency of 38 GHz.

Electrically conductive Two-dimensional Metal-Organic frameworks for superior electromagnetic wave absorption

Although metal–organic frameworks (MOFs)-derived composite materials have made remarkable achievements in the field of electromagnetic wave absorption, the investigation of intrinsic MOF materials for this purpose remains elusive. Herein, three two-dimensional MOFs, M3(HHTP)2 (M = Cu, Zn, Ni) were prepared by hydrothermal method, and their electromagnetic wave absorption properties and absorption mechanism were systematically studied. Due to the higher electronic conductivity, hexagonal prismatic rod-shaped Cu3(HHTP)2 exhibited better electromagnetic wave absorption performance than Zn/Ni3(HHTP)2. For Cu3(HHTP)2, a minimum return loss of is −56.45 dB, and the effective absorption bandwidth above −10 dB is 5.76 GHz and can cover the entire Ku band, which are comparable to those of the carbonized MOF-derived materials. This work broadens the application of intrinsic MOFs materials for electromagnetic wave absorption through a simple and effective strategy.

A simple and modular MIMO antenna system for closely spaced patch antennas

AbstractA simple, low cost and modular decoupling technique is proposed to achieve high isolation between very close antenna elements of a multiple‐input‐multiple‐output (MIMO) system without any complex decoupling structure, vias, or defected ground structure (DGS). A rectangular thin parasitic strip is used to decouple square patch elements, which are separated by an extremely close distance of at GHz. The proposed technique has achieved more than dB isolation between MIMO antenna elements with a minimum return loss of dB. A straightforward three‐step method is also proposed to shift the resonance frequency to some other frequency with similar isolation and impedance matching. All the important characteristics and performance parameters of the proposed design technique are analyzed, simulated, and verified through the measurement of the fabricated prototype.

Design of the Gradually Defect Patch Fractal Array Antenna for Unmanned Aerial Vehicle

This paper creatively proposes a new fractal iterative structure of a gradual defect patch and combines it with a rectangular array structure. Aiming at the performance requirements of the UAV system for multi-band compatible antennas, a gradual defect patch fractal array is designed. The radiation performance of the fractal array antenna was simulated by the method of moments, and antenna samples were made and the radiation performance was tested. Both simulation and actual measurement results show that this antenna has a working bandwidth of 5.5 GHz or more, a minimum return loss as low as -44 dB and excellent omnidirectional radiation capability. This antenna is compatible with the GPS system frequency band, Beidou system frequency band, all working frequency bands of the second to fifth generation mobile communication systems and the three working frequency bands of the RFID system, and is expected to be widely used as an unmanned aerial vehicle system antenna.