Dielectric Patch Antenna Research Articles

Microstrip dielectric patch antenna fabrication and characterization using ultra low permittivity and low temperature Co-fired LiAlSiO4 ceramics

LiBxAl1-xSiO4 (x = 0.02–0.1) ceramics were prepared by conventional solid-state method with a reduction in sintering temperature by up to 250–475 °C. The relative permittivity was significantly decreased by εr = 3.3–3.7, one of the lowest ever reported values among crystalline ceramics, while maintaining exceptional quality factors (Q×f = 25,000–28,000 GHz) and low temperature coefficients of resonance frequency (τf = −23 ∼ −16 ppm/°C). Furthermore, these LiBxAl1-xSiO4 ceramics possess a low density (∼2.3 g/cm3), making them highly promising for lightweight microwave devices. The potential application of LiB0.1Al0.9SiO4 ceramics in LTCC was assessed based on their ability to achieve low densification temperature and exhibit chemical compatibility with silver electrodes. A microstrip patch antenna with an operating frequency of 6.68 GHz, featuring high efficiency (91.88 %) and wide bandwidth (400 MHz), has been designed and fabricated from LiB0.1Al0.9SiO4 ceramics substrate, which provides a good application prospect for advanced wireless systems. The development of these ultra-low permittivity dielectric ceramics opens new potential to revolutionize the field of microwave dielectric ceramics.

A high-selectivity filtering DDPA with raised DDPs and metal vias

ABSTRACT A high-selectivity filtering dense dielectric patch (DDP) antenna (DDPA) with raised DDPs and metal vias is proposed in this paper. The proposed filtering DDPA has three resonant modes, the first two modes are TE 11 mode and the third mode is TE 12 mode. The first TE 11 mode is generated because of the centrally raised small DDP. The second TE 11 mode and the TE 12 mode are the modes of DDP itself. The proposed filtering DDPA has two radiation nulls (RNs). The low-frequency radiation null (LFRN) is generated by loading equal length parallel slots on the ground. DDP itself has a non-radiative high-frequency radiation null (HFRN). By loading symmetrical same metal vias on the DDP, the radiative TE 12 mode and the non-radiative TE 12 mode move to the low-frequency at the same time. That results in a wider passband and excellent high-frequency response. The proposed filtering DDPA is manufactured and measured for verification. The impedance bandwidth is 8.2% from 3.75 GHz to 4.07 GHz. The average gain is 7.7 dBi, and the average roll-off rate is 177 dB/GHz. The measured results prove that the proposed filtering DDPA has good radiation performance and high-selectivity.

Simulation of a Radio-Frequency Wave Based Bacterial Biofilm Detection Method in Dairy Processing Facilities

This paper describes the principles behind the radio-frequency (RF) sensing of bacterial biofilms in pipes and heat exchangers in a dairy processing plant using an electromagnetic simulation. Biofilm formation in dairy processing plants is a common issue where the absence of timely detection and subsequent cleaning can cause serious illness. Biofilms are known for causing health issues and cleaning requires a large volume of water and harsh chemicals. In this work, milk transportation pipes are considered circular waveguides, and pasteurizers/heat exchangers are considered resonant cavities. Simulations were carried out using the CST studio suite high-frequency solver to determine the effectiveness of the real-time RF sensing. The respective dielectric constants and loss tangents were applied to milk and biofilm. In our simulation, it was observed that a 1 µm thick layer of biofilm in a milk-filled pipe shifted the reflection coefficient of a 10.16 cm diameter stainless steel circular waveguide from 0.229 GHz to 0.19 GHz. Further sensitivity analysis revealed a shift in frequency from 0.8 GHz to 1.2 GHz for a film thickness of 5 µm to 10 µm with the highest wave reflection (S11) peak of ≈−120 dB for a 6 µm thick biofilm. A dielectric patch antenna to launch the waves into the waveguide through a dielectric window was also designed and simulated. Simulation using the antenna demonstrated a similar S11 response, where a shift in reflection coefficient from 0.229 GHz to 0.19 GHz was observed for a 1 µm thick biofilm. For the case of the resonant cavity, the same antenna approach was used to excite the modes in a 0.751 m × 0.321 m × 170 m rectangular cavity with heat exchange fins and filled with milk and biofilm. The simulated resonance frequency shifted from 1.52 GHz to 1.54 GHz, for a film thickness varying from 1 µm to 10 µm. This result demonstrated the sensitivity of the microwave detection method. Overall, these results suggest that microwave sensing has promise in the rapid, non-invasive, and real-time detection of biofilm formation in dairy processing plants.

Design and Validation of Water Based Dense Dielectric Patch Antenna (DDPA) for Microwave Communication around Frequency of 1GHz

Liquid antennas are distinct types of antennas that have been widely used due to their low profile, reconfigurable, and tunable features with steering abilities. In this paper, a low profile, high directivity, and good efficiency reconfigurable Water-Dense Dielectric Patch Antenna (DDPA) fed by the coaxial probe is presented. Distilled water becomes lossy above 1 GHZ frequency, so it is best suitable for lower-frequency applications. A thick substrate between the water patch and the ground plane is used. An impedance bandwidth of 7% with a maximum gain of 7.78 dBi, and radiation efficiency up to 71 % is obtained. This antenna can operate over the 967 to 1038 MHz band without a reduction in radiation efficiency. Simulated results are presented to validate the new design in both CST microwave studio and ANSYS HFSS which are the best simulating software for antenna designing. The comparison shows that the new antenna has a more compact size, and simpler structure, and is suitable for low-frequency applications.

Wideband Self-Decoupled Closely Placed Dielectric Patch Antenna Array Without Additional Structures

Wideband Self-Decoupled Closely Placed Dielectric Patch Antenna Array Without Additional Structures

A filtering dense dielectric patch antenna with rectangular silver strips

The filtering dense dielectric patch (DDP) antenna (DDPA) is proposed in this paper. Two pairs of rectangular silver strips are pasted on the top and bottom surfaces of DDP along the y-axis direction. This not only introduces the TM10-like mode, but also independently adjusts the resonant frequency of the TM10-like mode. The rectangular silver strips on the bottom surface of DDP can also make the DDPA obtain a radiation null. By pasting a pair of rectangular silver strips on the top surface of DDP along the x-axis direction, the resonant frequency of TE12 mode can be independently regulated. The resonant frequencies of TM10-like and TE12 modes of DDP form a passband. The proposed filtering DDPA is fabricated and measured to verify this idea. The simulation results are in good agreement with the measured results. The relative bandwidth of the proposed filtering DDPA is 4.64% (4.21–4.41 GHz), with an average gain of 5 dBi. The steep roll-off rates of the two sidebands are 120 and 320 dB/GHz, respectively.

A Wideband Decoupled Monolithic Multielement Dielectric Patch Antenna Array With Steerable Beam

A simple wideband decoupling method for monolithic multi-element dielectric patch (DP) antenna (DPA) array is presented in this letter. Thanks to the multimode of the DP resonator, the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">40</sub> and TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">42</sub> modes, which can be viewed as four TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> and four TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> modes, are simultaneously excited in the monolithic DPA. The introduction of the air slots etched in the DP not only isolates the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> -fields of the adjacent 1/4 TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">40</sub> (TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> ) or 1/4 TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">42</sub> (TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sub> ) modes simultaneously, but also synchronously tunes the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> and TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sub> modes so that the enhanced bandwidth can be maintained. Thus, the monolithic DPA can be regarded as a 1×4 wideband decoupled multi-element DPA array for MIMO application. For demonstration, a 1×4 monolithic wideband decoupled DPA array is fabricated and measured. Measured results show that the antenna array has the operation bandwidth of 4.92-5.83 GHz (16.9%). Within it, the isolations between the adjacent/nonadjacent elements are both better than 21.5 dB. And then the beam-steering DPA array can support maximum ±46º beam scanning in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> -plane.

Dielectric patch resonator and antenna

Dielectric patch resonator and antenna

Wideband Dielectric Patch Antenna With Stable Radiation Pattern

Wideband Dielectric Patch Antenna With Stable Radiation Pattern

Recent progress in dielectric resonator antenna: Materials, designs, fabrications, and their performance

Dielectric resonator antenna (DRA) has secured an esteemed position in the field of antenna engineering technology due to its versatile features, including compactness, light-weight, low loss, high radiation efficiency, ease of excitation, diverse feeding techniques, multiple excitation modes, ease of integration with passive and active microwave integrated circuit components, a wide variety of available materials, simple fabrication techniques, and high degree of flexibility over wide frequency range. This article presents a comprehensive up-to-date review of research carried out in the field of DRA technology which includes an overview of DRA technology, its history, present status, and prospects. The basic parameters of microwave dielectric ceramic materials and the classification of materials based on utilization and material parameters are briefly discussed. The applications of DRA in different fields of science, engineering, and technology, overview of different reported DRA shapes, and the feeding techniques used to excite different modes of DRA are mentioned. Based on the control of DRA permittivity, shape/geometry, feeding techniques, and structural modifications, performance parameters engineering of DRA and its achievable performance in terms of low profile, compactness, high gain, wide beam, circular polarization, wide bandwidth, DRA decoupling methods for multiple input multiple output arrays, dielectric patch antenna, filtering DRA, and reconfigurable DRA are discussed. Different techniques used to attain and enhance the particular performance of DRA are highlighted. This review article also dilates upon the fabrication processes and characterization methods of DRA microwave dielectric ceramics, which play a very vital role in controlling the performance and properties of DRA.

Broadband Dual-Polarized Dielectric Patch Antenna With High Isolation for Full-Duplex Communication

A broadband dual-polarized dielectric patch (DP) antenna is investigated for the in-band full-duplex applications. Taking full advantage of the multimode feature of DP, four resonant modes are excited and adjusted to form the two wide operating bands with orthogonal polarization. Among them, the dominant TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> mode and the high-order TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sub> mode provide the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i> -polarization while the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> mode and the antiphase TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">02</sub> mode provide the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</i> -polarization. In addition, the differential-fed scheme is applied to excite the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</i> -polarization modes for high isolation. Thanks to the features of low loss and low profile of DP, the proposed antenna obtains advantages in terms of radiation efficiency and profile height. An antenna prototype is fabricated and measured. The experimental results illustrate that the measured isolation during the whole band is better than 48 dB with a low profile of 0.05 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">min</sub> . The −10 dB bandwidths of two polarizations are 29.5% (4.71–6.1 GHz) and 18.9% (4.81–5.72 GHz), respectively.

Analysis of terahertz double dielectric structure patch antenna using nitride semiconductors

AbstractRecently, gallium arsenide (GaAs)‐based resonant tunneling diode (RTD) oscillators and indium phosphorus (InP)‐based Schottky barrier diode (SBD) receivers have been studied in the terahertz (THz) band. The THz devices for practical use should operate at room temperature, be small in size, and have high output power. Therefore, this study was focused on gallium nitride (GaN), which possesses excellent material properties, such as wide bandgap characteristics and heteroepitaxy on Si substrates. The GaN‐based oscillators and receivers are expected to be compact, operate at room‐temperature, and act as a high‐power device for the THz‐band devices. However, GaN has crystal defects, which can cause instability in device operations. A double dielectric structure patch antenna composed of Silicon Nitride (SiN) and Benzo Cyclo Butene (BCB) with different dielectric constants was proposed to realize a GaN‐based THz transmitter and receiver. The antenna characteristics were investigated using the Finite Difference Time Domain (FDTD) method. The results showed that the SiN has little effect on the radiation, whereas the BCB is strongly responsible for the radiation. Comparing the absolute gain between the double dielectric structure and the conventional structure using the SiN, it was confirmed that the double dielectric structure can improve the absolute gain.

A Wideband Circularly Polarized Dielectric Patch Antenna With a Modified Air Cavity for Wi-Fi 6 and Wi-Fi 6E Applications

In this letter, a novel wideband circularly polarized (CP) dielectric patch antenna (DPA) featuring low profile and relatively high gain property is investigated for Wi-Fi 6 and Wi-Fi 6E applications. Multiple modes of the feeding structure are excited which produces a wide impedance bandwidth (IBW). The introduction of FR4 branches in the air cavity helps to achieve a wider IBW of 48.3% (4.63–7.58 GHz). The E-field inside the air cavity acquires perturbation from the coupling of two dielectric patches (DP), which contributes to obtaining better CP performance. It can help achieve a wide axial ratio bandwidth of 35.3% ranging from 5.15 to 7.36 GHz for the proposed DPA. As the upper dielectric patch works as a director, a measured peak gain is increased to 8.47 dBic. Based on the multilayer PCB structure, the high permittivity dielectric patches loaded are packaged inside the FR4 substrates and fixed by branches. Therefore, a low-profile DPA with a height of 0.13 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is obtained and exhibits self-packaging for DP elements.

Analysis of Terahertz Double Dielectric Structure Patch Antenna Using Nitride Semiconductors

Recently, gallium arsenide (GaAs)-based resonant tunneling diode (RTD) oscillators and indium phosphorus (InP)-based Schottky barrier diode (SBD) receivers have been studied in the terahertz (THz) band. The THz devices for practical use should operate at room temperature, be small in size, and have high output power. Therefore, this study was focused on gallium nitride (GaN), which possesses excellent material properties, such as wide bandgap characteristics and heteroepitaxy on Si substrates. The GaN-based oscillators and receivers are expected to be compact, operate at room-temperature, and act as a high-power device for the THz-band devices. However, GaN has crystal defects, which can cause instability in device operations. A double dielectric structure patch antenna composed of Silicon Nitride (SiN) and Benzo Cyclo Butene (BCB) with different dielectric constants was proposed to realize a GaN-based THz transmitter and receiver. The antenna characteristics were investigated using the Finite Difference Time Domain (FDTD) method. The results showed that the SiN has little effect on the radiation, whereas the BCB is strongly responsible for the radiation. Comparing the absolute gain between the double dielectric structure and the conventional structure using the SiN, it was confirmed that the double dielectric structure can improve the absolute gain.

Fabrication of high-efficiency dielectric patch antennas from temperature-stable Sr3−xCaxV2O8 microwave dielectric ceramic

A novel high-efficiency dielectric patch antenna was fabricated using Sr3-xCaxV2O8 ceramics. A typically temperature-stable Sr3-xCaxV2O8 was achieved by tailoring the Ca2+ substitution to 30 mol% (x = 0.3), where well-balanced microwave dielectric properties were obtained (a near-zero value of +5.2 ppm/°C, a low εr ∼ 13.4, and a moderate Q×f ∼ 18,500 GHz). To manifest the application potentiality in wireless communication, a patch antenna was fabricated from the x = 0.3 ceramic based on the simulated result using the CST Microwave Studio software, and it showed a high simulated radiation efficiency (99.7%) and a gain (5.35 dBi) at 3.421 GHz. All results indicate that the Sr3-xCaxV2O8 ceramics have promising application potential for 5 G technology due to their prominent microwave dielectric properties, lightweight, and low cost.

Dielectric Patch Antenna Self-Decoupling by Proper Structural Parameters

This letter presents a simple and effective self-decoupling method for dielectric patch (DP) antenna (DPA) by choosing proper structural parameters, without adding extra components. By theoretical analysis, the attenuation constant of the employed fundamental TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> mode outside the DP is controlled by the structural parameters of the DP resonator, which is crucial for the decoupling between the two adjacent DPAs. It is found that the larger the attenuation constant of the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> mode, the better the port-to-port isolation in broadband, and then the radiation pattern can be stabilized. Under the premise of satisfactory isolation, the operational bandwidth and boresight gain of the DPA are studied for ensuring good antenna performance, exhibiting high design freedom and flexibility of the DPA. For demonstration, 1 × 2 closely spaced DPAs with optimal parameters are fabricated and measured. The simulated and measured results show good agreement.

Wideband low-profile H-shaped dielectric patch antennas based microwave dielectric ceramics

Dielectric patch antenna (DPA) has been extensively studied in recent years, especially for the application of 5G mobile communication system. In this paper, we proposed a notch structure of H-shaped DPA (HDPA) with wideband low-profile properties but without additional components. Temperature stable 0.65 CaTiO3–0.35 LaAlO3 microwave dielectric ceramic of high permittivity was utilized for fabricating the H-shaped dielectric patch, and the method of leveraging the multi-modal features of DPA was introduced. Further analysis of the antenna structure was accomplished by the simplified theoretical method. As a result, the H-shaped notch is properly ensembled in the dielectric patch to make the higher-order TM121 mode close to the dominant TM101 mode, greatly expanding the broadband of the HDPA. The accuracy of the proposed HDPA element model is evaluated by the commercial full-wave simulator CST Microwave Studio. For demonstration, a prototype of the proposed HDPA element operating in the microwave band (5-GHz) has been realized and measured.

Differential-Fed Pattern-Reconfigurable Dielectric Patch Antenna and Array With Low Cross-Polarization

A novel differential-fed dielectric patch (DP) antenna with beam steering capability is investigated in this communication. The TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mn</sub> mode in the DP resonator is theoretically analyzed to provide guidance for the subsequent antenna design. The high-order TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sub> mode that can be differentially excited is selected as the operating mode to further enhance the gain. Based on this, three parallel coupling slots loaded with p-i-n diodes are used as a beam steering structure. By controlling the ON-/OFF-state of the p-i-n diodes to change the <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> -field distribution of the TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sub> mode, the main beam can be switched to five directions. The measured gain of each state is higher than 7 dBi, and the peak value reaches 8.1 dBi. The beam steering structure and differential-fed scheme show good coordination, which effectively suppresses the deterioration of cross-polarization caused by structural asymmetry. The cross-polarization of each state is lower than −26 dB. To further verify the scalability of the proposed ideal, a 1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 4 array fed by two dual Marchand baluns is implemented, which well maintains the beam steering capability and low cross-polarization. Reasonable agreement is obtained between the simulated and measured results. The proposed DP antenna provides a suitable candidate for indoor wireless communication.

Dual-polarized elliptic-H slot-coupled patch antenna for 5G applications

A dual-polarized, slot-coupled dielectric patch antenna design is presented in sub-6 GHz for 5G base stations. Proposed antenna is implemented using two dielectric patch layers (main patch and parasitic patch) above a feeding line layer. Excitation is realized by crossed elliptic-H slots in order to create orthogonal ± 45$^{\circ}$ polarizations. Through the use of patches at proper heights together with elliptic-H slots, significant improvement in impedance bandwidth, matching level, isolation and front-to-back ratio is acquired. Prototype antenna has an impedance bandwidth of 18.5\% (3.23--3.85 GHz) for $ S_{11} $, $ S_{22} $ $

Design of a low-profile high-selectivity filtering dense dielectric patch antenna

In this paper, a filtering dense dielectric patch (DDP) antenna (DDPA) with low-profile and high-selectivity is proposed with thickness of 0.024λ0. By etching an annular gap in the DDP, not only the TM11 mode and TM12 mode are successfully adjusted to the adjacent frequency, but also the high-order harmonics are suppressed. Consequently, both of the operating bandwidth and stopband bandwidth of the proposed DDPA can be enhanced. To improve the skirt selectivity, an adjustable radiation null (RN) is introduced at the lower edge of the passband by using a cross-shaped microstrip feed structure. Due to the mutual coupling between the cylindrical DDP and annular DDP, another adjustable RN is introduced at the upper edge of the passband. Hence, the proposed DDPA can realize the filtering function without additional filtering circuit. For demonstration, a prototype is fabricated and measured. The measured results prove that the proposed design has a relative impedance bandwidth of 8.6% (3.44–3.75 GHz), a peak gain of 8.1 dBi and a high roll-off rate of 180.8 dB/GHz. The proposed design has great application prospects in modern wireless communication system.