Design of Dielectric Resonator Liquid Yagi-Uda Antenna (original) (raw)
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Tunability of Liquid Dielectric Resonator Antennas
Antennas and Wireless Propagation Letters, 2000
Dielectric resonator antennas (DRAs) have in the past been used most often at frequencies in the GHz portion of the spectra. This letter presents a novel 50-MHz DRA that uses water as the dielectric. For purposes of keeping the antenna tuned to a specific frequency, and for using the antenna at different frequencies, this antenna can utilize a pump to alter the level of water in the DRA, thus, altering its resonant frequency. An electronic technique for retuning the feed probe is also presented where varactor diodes are biased to provide a good impedance match across a range of approximately 50 to 100 MHz. These antennas may provide a compact solution at lower frequencies especially where a directional pattern may be required. The liquid dielectric not only provides frequency tuning but simple deployment and a reducible radar cross section.
2016
Abstract—Dielectric resonator antennas (DRAs) have in the past been used most often at frequencies in the GHz portion of the spectra. This letter presents a novel 50-MHz DRA that uses water as the dielectric. For purposes of keeping the antenna tuned to a specific frequency, and for using the antenna at different frequen-cies, this antenna can utilize a pump to alter the level of water in the DRA, thus, altering its resonant frequency. An electronic technique for retuning the feed probe is also presented where varactor diodes are biased to provide a good impedance match across a range of approximately 50 to 100 MHz. These antennas may provide a compact solution at lower frequencies especially where a directional pattern may be required. The liquid dielectric not only provides frequency tuning but simple deployment and a reducible radar cross section. Index Terms—Dielectric antennas, liquid dielectrics, varactor tuners. I.
An Investigation of Water Antennas
An investigation of water antenna with a relative permittivity of 81 and a variable conductivity has been undertaken. Two issues are addressed in the paper. Firstly, the relationship between conductivity and radiation efficiency is investigated. Two extreme cases are examined. Secondly, a new feeding design for water antenna is proposed and good return loss, radiation efficiency and radiation pattern are obtained. It has demonstrated that a water antenna can be treated as a dielectric resonant antenna or a conducting antenna-depending on the conductivity. This type of antenna has a great potential to be made as a reconfigurable antenna for some applications.
Transparent Water Dense Dielectric Patch Antenna
2017
The proposed antenna is a transparent water dense dielectric patch antenna which is fed by an L-shaped probe. The operating mechanism of the proposed antenna is similar to the standard metallic patch antenna. A study reveals that the gain of the antenna can be increased if the water patch is brought close to the L-shaped probe but the distance between the water patch and the L-shaped probe should be atleast 1 mm. A maximum gain of 7.3 dBi, return loss of 18.4 dB and impedance bandwidth of 575 MHz was achieved. It had symmetrical unidirectional patterns.
Metasurfaced, Broadband, and Circularly Polarized Liquid Antennas Using a Simple Structure
IEEE Transactions on Antennas and Propagation, 2019
A novel broadband circularly polarized (CP) antenna using organic ionic liquid resonators is presented in this paper for the first time. The antenna is excited by inserting a new feeding structure into the liquid which is relatively simple but significantly improves the bandwidth and CP performance of traditional single probe-fed dielectric resonator antennas (DRAs). The proposed liquid antenna is loaded with a meta-surface (MS) to further improve the impedance matching and CP characteristics. A design example of the proposed antenna shows a relatively wide fractional impedance bandwidth and CP bandwidth of 51.4% and 34.2%, respectively. In addition, the proposed liquid DRA has a reduced structural complexity and a compact size compared with the conventional DRAs with a similar performance. The design methodology presented in this work can be further exploited for a range of new liquid DRA designs and expand the design freedom and flexibility of such antennas which may have significant implications in future antenna designs using the new liquid materials.
A novel liquid antenna for wearable bio-monitoring applications
2008 IEEE MTT-S International Microwave Symposium Digest, 2008
The performance of the most commonly used metal antennas close to the human body is one of the limiting factors of the performance of bio-sensors and wireless body area networks (WBAN). Due to the high dielectric and conductivity contrast with respect to most parts of the human body (blood, skin, ...), the range of most of the wireless sensors operating in RF and microwave frequencies is limited to 1-2 cm when attached to the body. In this paper, we introduce the very novel idea of liquid antennas, that is based on engineering the properties of liquids. This approach allows for the improvement of the range by a factor of 5-10 in a very easy-to-realize way, just modifying the salinity of the aqueous solution of the antenna. A similar methodology can be extended to the development of liquid RF electronics for implantable devices and wearable realtime bio-signal monitoring, since it can potentially lead to very flexible antenna and electronic configurations.
Micromachines
In this study, a novel microfluidic frequency reconfigurable and optically transparent water antenna is designed using three-dimensional (3D) printing technology. The proposed antenna consists of three distinct parts, including a circularly shaped distilled water ground, a sea water-based circular segmented radiator, and a circularly shaped distilled water-based load, all ingeniously constructed from transparent resin material. The presented antenna is excited by a disk-loaded probe. The frequency of the antenna can be easily tuned by filling and emptying/evacuating sea water from the multisegmented radiator. The radiator consists of three segments with different radii, and each segment has a different resonant frequency. When the radiator is filled, the antenna resonates at the frequency of the segment that is filled. When all the radiator segments are filled, the antenna operates at the resonant frequency of 2.4 GHz and possesses an impedance bandwidth of 1.05 GHz (40%) in the ran...
Cylindrical Dielectric Resonator Antenna-Based Sensors for Liquid Chemical Detection
Sensors, 2019
A compact, cylindrical dielectric resonator antenna (CDRA), using radio frequency signals to identify different liquids is proposed in this paper. The proposed CDRA sensor is excited by a rectangular slot through a 3-mm-wide microstrip line. The rectangular slot has been used to excite the CDRA for H E M 11 mode at 5.25 GHz. Circuit model values (capacitance, inductance, resistance and transformer ratios) of the proposed CDRA are derived to show the true behaviour of the system. The proposed CDRA acts as a sensor due to the fact that different liquids have different dielectric permittivities and, hence, will be having different resonance frequencies. Two different types of CDRA sensors are designed and experimentally validated with four different liquids (Isopropyl, ethanol, methanol and water).