High Efficiency Bandwidth VHF Electrically Small Antennas Through Direct Antenna Modulation

Santos, Jean Paul; Fereidoony, Foad; Hedayati, Maziar; Wang, Yuanxun Ethan

doi:10.1109/tmtt.2020.3016381

Cited by 13 publications

(6 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because the CLLA can be modeled as a simple RLC circuit with a transformer, the whole DAM system can be modeled as a circuit while including the transistors used for switching. As an example, a BFSK DAM [21] system is seen in Fig. 1.…”

Section: Frequency Shift Keyed Direct Antenna Modulationmentioning

confidence: 99%

“…This measures the radiation efficiency along with the instantaneous bandwidth of the antenna [25]. Specifically, a way to quantify the improvement of the DAM antenna in comparison with the CLLA called [21] which compares the EB of both antennas = = (16) where EBDAM and EBCLLA is the EB of the DAM and CLLA, respectively. The efficiencies, eDAM and eCLLA can be calculated by the ratio of the sum of the received tones, shown in Fig.…”

Section: Far-field Measurements Of 4fsk Direct Antenna Modulationmentioning

confidence: 99%

“…Previously it was shown that the use of high figure of merit (FoM) transistors results in an FSK DAM system that capable of even greater data rates due to the increased frequency of separation between carriers [21]. However, DAM was limited to a binary modulation symbol.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Toward a Spectrally Efficient FSK Direct Antenna Modulation

et al. 2020

Self Cite

View full text Add to dashboard Cite

Antennas in platforms where the physical dimensions are significantly smaller than the wavelength of the frequency of interest are limited to narrowband operations. A technique that enables transmission of such signals through narrowband antennas is called Direct Antenna Modulation (DAM). DAM utilizes switching circuitry to directly modulate the antenna at its maximum energy moments synchronized with the input RF signal. In this paper, we propose a method of attaining higher-order, N, frequency shift keyed, NFSK, modulation through a high Quality-factor electrically small antenna to achieve higher bit rates and better spectral efficiency within an instantaneous bandwidth. A DAM antenna transmitting a frequency shift keyed signal using four carrier frequencies, 4FSK, was designed, prototyped, and measured. Its electrical size is 0.018λ x 0.02λ. A pseudorandom 8-bit and 16-bit sequence were transmitted through the 4FSK DAM antenna and received in the far-field. The results show that such a topology provides a roadmap in attaining even higher modulation orders, thus, higher spectral efficiency. INDEX TERMS electrically small antennas, direct antenna modulation, time-varying electromagnetics, high-efficiency bandwidth antenna

show abstract

Section: Frequency Shift Keyed Direct Antenna Modulationmentioning

confidence: 99%

Section: Far-field Measurements Of 4fsk Direct Antenna Modulationmentioning

confidence: 99%

See 1 more Smart Citation

Toward a Spectrally Efficient FSK Direct Antenna Modulation

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…The small size antennas in medical applications are suited for use in and around human bodies. There are multiple antenna approaches [ 1 ] [ 2 ] [ 3 ] [ 4 ] for the E/H linearity within the human body, while lacks the portable size feature that enables integrating them around the human tissue sizes. The rapid development in devices that emit Radio Frequency Electromagnetic Fields (RF-EMF) has sparked a growing interest in their interaction with biological systems and their beneficial effects on human health.…”

Section: Introductionmentioning

confidence: 99%

Numerical Modeling and Computer Simulation of a Meander Line Antenna for Alzheimer’s Disease Treatment, a Feasibility Study

Perez¹,

Rahmani²,

Morisaki³

et al. 2023

JBM

View full text Add to dashboard Cite

Alzheimer's disease (AD) is a brain disorder that eventually causes memory loss and the ability to perform simple cognitive functions; research efforts within pharmaceuticals and other medical treatments have minimal impact on the disease. Our preliminary biological studies showed that Repeated Electromagnetic Field Stimulation (REFMS) applying an EM frequency of 64 MHz and a specific absorption rate (SAR) of 0.4 -0.9 W/kg decrease the level of amyloid-β peptides (Aβ), which is the most likely etiology of AD. This study emphasizes uniform E/H field and SAR distribution with adequate penetration depth penetration through multiple human head layers driven with low input power for safety treatments. In this work, we performed numerical modeling and computer simulations of a portable Meander Line antenna (MLA) to achieve the required EMF parameters to treat AD. The MLA device features a low cost, small size, wide bandwidth, and the ability to integrate into a portable system. This study utilized a High-Frequency Simulation System (HFSS) in the design of the MLA with the desired characteristics suited for AD treatment in humans. The team designed a 24-turn antenna with a 60 cm length and 25 cm width and achieved the required resonant frequency of 64 MHz. Here we used two numerical human head phantoms to test the antenna, the MIDA and spherical head phantom with six and seven tissue layers, respectively. The antenna was fed from a 50-Watt input source to obtain the SAR of 0.6 W/kg requirement in the center of the simulated brain tissue layer. We found that the E/H field and SAR distribution produced was not homogeneous; there were areas of high SAR values close to the antenna transmitter,

show abstract

“…Frequency shift keying (FSK) is of particular interest for DAM schemes because it requires the most bandwidth for a given data rate while being relatively energy efficient. While the DAM concept was originally developed for FSK at very low frequency [7–12], it was recently rediscovered for higher frequency FSK systems and demonstrated in several different papers [13–18, 23]. It is mentioned in several prior studies that energy storage and transfer is fundamental to the scheme but a model and quantitative understanding of how energy storage (or lack thereof) affect the signal characteristics has not been investigated in much detail.…”

Section: Introductionmentioning

confidence: 99%

Transient analysis of dynamically switched frequency shift keyed transmitters

Srivastava

Adams

2022

IET Microwaves Antenna & Prop

View full text Add to dashboard Cite

A dynamically switched matching network for transmitting a wideband frequency shift keyed (FSK) signal from an electrically small monopole antenna is studied. The effects of switch synchronization, frequency deviation, the antenna's impedance, and Q-factor at the two carrier frequencies are studied. It is found that the average energy per bit of the transmitted FSK waveform is maximum when the loss of reactive energy between states transition is minimised by switching it at the instant of peak voltage across the antenna's terminals. However, a switching network topology that stores more energy is shown to be less sensitive to the synchronization condition. In addition, we show that this dynamically switched system transmits more bit energy when the carriers are closely spaced due to a smaller change in stored energy levels between states. Results are presented using a detailed analytical study and full wave simulation. Near field measurements from a monopole antenna circuit model show that under proper conditions, an FSK signal can be transmitted at a rate 7 times greater than the bandwidth of the transmit antenna with minimal signal quality degradation.

show abstract

High Efficiency Bandwidth VHF Electrically Small Antennas Through Direct Antenna Modulation

Cited by 13 publications

References 34 publications

Toward a Spectrally Efficient FSK Direct Antenna Modulation

Toward a Spectrally Efficient FSK Direct Antenna Modulation

Numerical Modeling and Computer Simulation of a Meander Line Antenna for Alzheimer’s Disease Treatment, a Feasibility Study

Transient analysis of dynamically switched frequency shift keyed transmitters

Contact Info

Product

Resources

About