Dielectric Patch Antenna Research Articles

Fabrication of Wideband Low‐Profile Dielectric Patch Antennas from Temperature Stable 0.65 CaTiO3–0.35 LaAlO3Microwave Dielectric Ceramic

AbstractIn this paper, the medium dielectric constant 0.65CaTiO3‐0.35LaAlO3(CTLA) composite microwave ceramic is employed to introduce in dielectric patch antennas (DPA). Typical, high‐performance microwave dielectric properties ofεr ≈ 44.8,Q × f ≈ 43 950 GHz@3.67 GHz andTCF ≈ 0 ppm °C–1can be obtained by solid‐state reaction method in CTLA composite microwave ceramics sintered at 1450 °C for 2 h. Then, the CTLA composite ceramic patch fired with silver coating is mounted on the Rogers RO4003C substrate operating as a magnetic wall boundary. A simplified cavity‐like theoretical model is used to analyze the proposed DPA structure and the accuracy of this antenna model is evaluated by the theoretical results from a commercial CST Microwave Studio 2019. Based on this, the CTLA composite ceramic physical property is modified to enhance the radiation efficiency and reduce profile of the DPA. The higher‐order TM121mode is brought close to the dominant TM101mode by taking advantage of the multimode characteristics of the dielectric patch resonator and introducing a sintered silver slot in the ceramic dielectric patch. For demonstration, the proposed DPA prototype operating in the multiprobe antenna near the field measurement system is implemented and measured.

Ultra-Wideband Coplanar Vivaldi Antenna Array With Dielectric Patch Antenna for Grating Lobes Suppression

This paper details a new approach for enhancing the radiation characteristics of a coplanar Vivaldi antenna (CVA) array. First, the inter–element mutual coupling is reduced by introducing slots in the conventional CVA array. Then, a low-profile dielectric patch antenna (DPA) is situated between the CVA flares when it acts as a travelling wave radiator at the higher frequency band. The DPA is excited by the loop current at the radiation part of the CVA and a set of TE modes with omnidirectional radiation patterns are excited. This combination enhances the directivity in the broadside direction of the CVA by suppressing the grating lobes by as much as 10 dB. The 4×1 linear array covers the frequency range of 2.77-13.6 GHz, with 132% fractional bandwidth. Then, four of the proposed linear arrays are connected to constitute an 8×2 planar array to achieve a gain of 15.2-24.6 dBi. The proposed arrays are fabricated, tested and mounted on a small (Unmanned Aerial System) sUAS for radar measurements. The real-life field radar results with the proposed arrays are presented in this paper including the echogram of the scanned area.

Water dense dielectric patch antenna with wide‐band and circular polarization reconfigurability

Water dense dielectric patch antenna with <scp>wide‐band</scp> and circular polarization reconfigurability

Wideband low‐profile dual‐polarized dielectric patch antenna with metallic pins

AbstractIn this article, a lowprofile dual‐polarized dielectric patch antenna (DPA) using TM101 and TM121 modes is proposed for achieving the impedance bandwidth (BW) enhancement. By introducing four metallic pins in a dielectric patch resonator (DPR), the TM121 mode is shifted to low frequencies while TM101 mode is shifted to high frequencies. Therefore, the two modes can be close to each other for obtaining wide working bandwidth. Moreover, two orthogonal aperture‐coupled feeders are employed to excite the proposed DPR to realize the dual polarization. Finally, the proposed antenna is fabricated and measured. The simulated and measured results show that the 10 dB impedance matching bandwidth is 15.2% (5.05–5.87 GHz), while maintaining the low‐profile characteristics with the height of 0.07λ0 (λ0 is free space wavelength at the center frequency f0). In addition, the antenna achieved a peak gain of 8.55 dBi in the operating frequency.

Water dielectric microstrip patch antenna: case study at ISM 2.4 GHz

ABSTRACT Transparent antennas are becoming important in the wireless field since they can be integrated in combination with solar cells placed underneath the transparent antenna to make the antenna system compact. In this regard, water is used in this study. The behaviour of a water dielectric patch antenna is presented to find the influence of the thickness of water and the type of water used on the efficiency, gain and radiation pattern of the antenna. The water patch antennas operate at the ISM (Industrial, Scientific, Medical) band of 2.4 GHz. Measured results are compared with a classical square patch made from copper where the water patch performs with a comparable efficiency and similar radiation patterns.

A differential‐fed dual‐polarized antenna with gain enhancement using hollow dielectric patch resonator

A differential-fed dual-polarized dielectric patch (DP) antenna with high gain, wide bandwidth, and high isolation is investigated in this article. Based on the analysis of the anisotropic property of the DP antenna, further exploration of gain enhancement is carried out. The introduction of the square air hole in the substrate to obtain a hollow DP resonator is a crucial technique. It not only increases the electromagnetic radiation from the sidewalls of the DP resonator to further improve the gain to 8.9 dBi, but also shifts the dominant TM101 mode upward to get close to the higher-order TM121 mode to achieve bandwidth expansion of 19.4%. By using the differential-fed scheme to excite the TM101 mode, TM121 mode and their degenerate modes, dual-polarization operation and high isolation level can be obtained simultaneously.

Low-Profile Frequency-Reconfigurable Dielectric Patch Antenna and Array Based on New Varactor-Loading Scheme

A novel varactor-loading scheme is proposed for dielectric patch (DP) antenna to design frequency-reconfigurable antenna and array. Benefiting from the stacked structure of the DP antenna, the microstrip line is partially inserted between the DP and substrate in a simple way, and the extended part can be used to load the varactor, thereby realizing the function of frequency tunability. At the same time, the loading element has a slight effect on the radiation patterns of the proposed antenna. The impacts of the microstrip line dimensions on frequency tuning range (TR) and radiation efficiency of the antenna are investigated in detail. It is found that an appropriate inserted length of the microstrip line is a key to achieve a good tradeoff between the frequency TR and radiation efficiency. The resultant frequency-reconfigurable DP antenna shows a TR of about 15% and radiation efficiency of more than 50% across the frequency-TR. For demonstration, the DP antenna element and 2×2 array prototypes operating in the C-band are implemented and measured. The simulated and measured results with a good agreement are presented to verify the proposed idea.

A low‐profile circularly polarized dielectric patch antenna with bandwidth expansion

A new technology for expanding the axial ratio (AR) bandwidth of the circularly polarized (CP) dielectric patch (DP) antenna while maintaining the low-profile characteristic is proposed for the first time. By making full use of the multimode characteristic of the DP resonator, two pairs of degenerate modes (ie, TM101 and TM011, TM121 and TM211) are selected for the broadband design. The key to the proposed technology is that according to the EM field distribution of the two pairs of degenerate modes, four air holes are introduced in the DP and their position and size are elaborately designed to discriminately control the frequency of the two pairs of degenerate modes. Then, these modes become close and are merged to effectively expanding the AR bandwidth of the low-profile CP DP antenna. For demonstration, a prototype centered at about 10 GHz is designed, fabricated, and measured. The measured results exhibit that the proposed CP DP antenna with a low profile of 0.07λ0 owns a 3 dB AR bandwidth of 9.7% and a peak gain of 7.66 dBic. Good agreement is observed between simulated and measured results.

A Wideband Filtering Dielectric Patch Antenna With Reconfigurable Bandwidth Using Dual-Slot Feeding Scheme

A wideband filtering dielectric patch (DP) antenna with reconfigurable bandwidth is investigated in this paper. Adjusting the aspect ratio of the DP resonator can make the high-order TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">121</sub> mode close to the dominate TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">101</sub> mode to facilitate the design of wideband filtering DP antenna. Meanwhile, the high-order TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">111</sub> mode is adjacent to the TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">121</sub> mode and then used as a non-excitation and non-radiation mode for producing an upper band-edge radiation null. On this basis, two slots with different sizes in parallel are introduced into the ground plane to excite the DP resonator, resulting in a lower band-edge radiation null, which sharpens the lower band-edge roll off. A pair of slits between the two coupling slots are incorporated and the varactor diodes are loaded on the slits to tune the electrical distance of the coupling slots, thereby electrically controlling the frequency of the lower band-edge radiation null. In this way, the fractional bandwidth (FBW) of the resultant filtering antenna can be flexibly tuned from 21% to 15.3%. A prototype has been designed, fabricated, and measured. Reasonable agreement was obtained between the simulated and measured results.

A Wideband Dual-Slot Coupled Multiple Dense Dielectric Patch Antenna

A dual-slot coupled multiple dense dielectric (DD) patch antenna is proposed to achieve wide bandwidth. The multiple DD patches operating at quasi-TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> mode and quasi-TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> mode, which is excited by the dual slots. In addition, the dual slots also function as an effective radiator as with DD patches. Thus, five modes including two modes of DD patches and three modes of the dual slots can be obtained to support wide bandwidth. Compared with the reported DD patch antennas, the proposed design exhibits wide bandwidth and relatively high gain with a finite ground size. For demonstration, one prototype operating at 8.98 GHz is fabricated with the ground size of 0.63λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.78λ <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 wavelength in the free space at the center frequency), the 10 dB impedance matching bandwidth of 81.9%, and the peak gain of 9.27 dBi.

The effects of TiO2 addition on microwave dielectric properties of Y3MgAl3SiO12 ceramic for 5G application

In this paper, thermal stable Y3MgAl3SibO12-TiO2 microwave composite ceramics were firstly fabricated by the high temperature solid phase reaction method. The influence of the sintering temperature, microstructure on microwave dielectric properties of Y3MgAl3SiO12 by doping TiO2 were investigated in detailed. TiO2 addition reduced the ceramic sintering temperature and improved the distribution of grain size. The negative temperature coefficient of resonant frequency (τf = −32 ppm/°C) of Y3MgAl3SiO12 was adjusted to near zero value. 0.8Y3MgAl3SiO12-0.2TiO2 ceramic sintered at 1475 °C for 6 h achieved the optimized microwave dielectric properties: εr = 12.2, Q × f = 21,050 GHz, τf = +5.2 ppm/°C, which indicated that 0.8Y3MgAl3SiO12-0.2TiO2 is a potential candidate for dielectric patch antenna and substrate.

Differential-Fed Dual-Polarized Dielectric Patch Antenna With Gain Enhancement Based on Higher Order Modes

A differential-fed gain-enhanced dual-polarized dielectric patch antenna operating at higher order TM121 and TM321 modes is investigated in this letter. The introduction of grounded bars in a conventional square dielectric patch resonator (DPR) is a key technique in the proposed design. It not only moves the higher order TM121 mode upwards to enhance the gain of the antenna, but also enables the higher order TM321 mode to be excited and combined with TM121 mode to expand the bandwidth. Their corresponding degenerate modes in the DPR are used to generate a dual-polarized operation. By using two identical pairs of differential feeding lines to excite the proposed DPR, several advantages such as high isolation and low cross polarization can be obtained. For demonstration, an antenna prototype centered at about 4.9 GHz is implemented and measured. The simulated and measured results are given, showing a good agreement.

Effects of added Secondary Dielectric material on the Performance of a Microstrip patch Antenna

Micro strip patch antennas are normally fabricated on the surface of a dielectric material. Due to various reasons, the replacement of the surface material and modifications in area are not possible, once the antenna is fabricated. In some cases, the operating frequency and bandwidth of the antenna needs to be altered without changing the substrate. This paper investigates a dual dielectric patch antenna and analyses the performances of the antenna under the combined dielectric layers inside the cavity. Initially, a patch antenna is designed for a resonant frequency with a widely used dielectric material, FR4 and after which another dielectric layer is added. The performance of the antenna is evaluated using Method of moments solver in ADS software. The thickness sharing percentage of the secondary dielectric material was linearly increased from 10% to 90% in simulation. The analysis shows an emergence of another band due to the introduction of secondary dielectric layer. Measurements also confirm the simulation results and notable change in reflection coefficient with bandwidth enhancement is observed.

Wideband Low-Profile Dielectric Patch Antenna and Array With Anisotropic Property

A dielectric patch (DP) resonator (DPR) with silver-coated slots is investigated for designing wideband low-profile antenna in this communication. The low-profile DPR can be treated as an anisotropic dielectric resonator (DR) for analysis. A new equation for calculating the effective dielectric constant of the DPR operating at the TM modes is proposed. Based on this, the anisotropic property is investigated to enhance the gain of DP antenna (DPA). It is found from the theoretical analysis that the resultant antenna is a good compromise between the traditional microstrip patch antenna (MPA) and dielectric resonator antenna (DRA) in terms of profile, gain, efficiency, and design freedom. By making full use of the multimode characteristic of the DPR, the silver-coated slots are introduced on the DP to shift high-order TM121 mode close to TM101 mode. As a result, the bandwidth of the antenna can be significantly expanded. For demonstration, the DPA element and 1×4 array prototype operating in the microwave band (5 GHz) are implemented and measured.

Design of a compact dense dielectric patch antenna based on half‐cut technique

In this article, a half-cut rectangular dense dielectric patch (DDP) with one grounded side plane is theoretically investigated for designing a compact low-profile antenna. According to the properties and the E-field distribution of the dominant TM101 mode, the half-wavelength (λ/2) DDP can be bisected by effectively shorting the center plane to the ground, resulting in a miniaturized half-cut λ/4 DDP. The size of the DDP is effectively reduced by 50% while maintaining the original resonant frequency of the dominant TM101 mode. The half-cut λ/4 DDP can be well excited through aperture coupling for antenna design. The design procedure of the proposed antenna is given in detail. For demonstration, an antenna prototype centered at 4.15 GHz is implemented and measured. The simulated and measured results are given, showing good agreement.

Magnesium fluoride doped MgTiO3 ceramics with ultra-high Q value at microwave frequencies

Microwave ceramic with ultra-high Q value is one of the most significant classes of material to realize the miniaturization and integration of microwave devices. In this paper, to improve the microwave dielectric properties of ceramics, MgTiO3-x wt.% MgF2 (x = 0, 3, 4, 5, and 6) microwave ceramics with high-quality factor were synthesized by solid-state reaction method. The effects of MgF2 addition on the phase composition, sintering behavior, and microwave dielectric properties of MgTiO3 were investigated. In comparison to pure MgTiO3, our study demonstrates that the Q × f values can be dramatically enhanced with the doping of MgF2. After being sintered at 1300 °C for 4 h, the MgTiO3-3 wt.% MgF2 showed the best microwave dielectric properties of εr ∼18.09, Q × f ∼262,900 GHz (at 8.98 GHz) and τf ∼ −41.5 ppm/°C. The outstanding performance of MgF2 doped MgTiO3 ceramics provides a solid foundation for widespread applications of microwave dielectric substrates, resonators, filters and patch antennas in modern wireless communication equipment.

Microstructure and microwave dielectric characteristics of magnesium fluoride additive to MgTiO3-(Ca0.8Sr0.2)TiO3 ceramics

In this paper, the MgF2-doped (1 − x)MgTiO3-x(Ca0.8Sr0.2)TiO3 (x = 0.01–0.09) ceramics with high-quality factor (Q × f) and near-zero temperature coefficient of the resonant frequency (τf) were synthesized by solid-state reaction method. The effects of MgF2 addition on the phase composition, sintering behavior, and microwave dielectric properties in this system were completely investigated. Furthermore, the sintering temperature of 3 wt% MgF2-doped 0.95MgTiO3-0.05(Ca0.8Sr0.2)TiO3 ceramics can be lowered to 1225 °C. Then, the best microwave dielectric properties of εr ∼ 19.99, Q × f ∼ 90,100 GHz (at 8.72 GHz) and τf ∼ −2.9 ppm/°C were obtained. It provides a solid foundation for widespread applications of microwave dielectric substrates, filters, resonators, and patch antennas in modern wireless communication equipment.

Fully substrate‐integrated dense dielectric patch antenna and array

Here, a fully substrate-integrated dense dielectric patch (DDP) antenna and array is proposed. The DDP resonator based on high-permittivity substrate on the top layer is reasonably constructed and implemented by making full use of the printed circuit board (PCB) technology, whose characteristics are theoretically analysed in detail. Accordingly, the DDP antenna element operating at the dominate TM 101 mode (cavity mode) is designed, which is fed by the substrate-integrated strip line (SISL) through a feeding slot. The slot resonant frequency is close to the TM 101 mode of the DDP so that the antenna impedance bandwidth (BW) is extended. For further demonstration, a 1 × 4 array based on the DDP antenna element is designed and fabricated. The simulated and measured results are given, showing good agreement. The impedance BW for | S 11 | <; -10 dB is about 8.4% and the peak gain reaches 11.77 dBi.

High‐efficiency circular dense dielectric patch antenna with frequency selectivity

A circular dense dielectric (DD) patch antenna realised by stacking an upper DD patch on the lower DD patch is proposed to achieve high efficiency and frequency selectivity. The high efficiency is attributed to the non-metallic radiators and the radiations of both lower and upper DD patches operating at TM11 mode. To achieve higher frequency selectivity than that of the reported DD patch antennas, the opposite E-field distribution inside the upper DD patch and the quarter-wavelength open-circuit stub produce two radiation nulls near the lower band-edge, while the opposite E-field distribution inside the lower DD patch and the opposite E-field distribution at the edges of the two DD patches produce two radiation nulls near the upper band-edge. For demonstration, a prototype covering the fifth generation (5G) band (3.4–3.6 GHz) achieves the simulated radiation efficiency of 96%, the measured peak gain of 9.2 dBi, 10 dB impedance bandwidth of 12.3%, four radiation nulls, and the cross-polarisation rejection larger than 22 dB within the 3-dB beam range at the centre frequency. The results show the features of high efficiency, multiple radiation nulls, wide bandwidth and high gain simultaneously while the reported DD patch antennas just have part of the features.

Multi-Band Hybrid Dielectric Resonator Antenna for Different Applications

In this written communication, a report of multi-band hybrid cylindrical ring dielectric resonator antenna is proposed. The proposed antenna outline comprises ring formed by dielectric resonator antenna and H-shaped patch antenna. The proposed antenna design shows multi-band characteristics. The simulated results are shown by using HFSS simulation software. The resonance frequency of the proposed radiator is 2.4 GHz, 3.4 GHz, 4.1 GHz and 5.2 GHz with return loss of-20 dB, -25 dB, -35 dB and-32 dB, respectively. The proposed antenna is applicable to Bluetooth, WLAN, WiMAX and satellite applications.