Modified Bowtie Antenna Research Articles

Ultra-wideband and high isolation using defected ground structure modified bowtie antenna array for through wall imaging applications

The design and analysis of an ultra-wideband with high isolation characteristics, utilizing a modified bowtie antenna and coplanar waveguide feeding technique is presented in this paper. Grooves are added to the ground plane's entire structure to reduce the capacitive coupling between the patch and the ground plane. The grooves in the ground plane enhance the impedance matching and radiation efficiency across the ultrawideband frequency range. Also, defected ground structures (DGS) are used to improve isolation between the two antennas. It is novel and different in that it uses defective ground structures (DGS) to provide high isolation (−<50dB) with a high gain of 6.5 dBi and a large impedance bandwidth (155%). Compared to other documented methods, the antenna's design step is very simple, the overall size is small, larger bandwidth (13.5 GHz) and achieves high isolation due to DGS.

Modified bow-tie antenna array with efficient electric near-field enhancement for terahertz band

Antenna arrays can induce strong electric near-field enhancement to improve the performance of biological imaging resolution, macromolecule detection sensitivity, and sensing accuracy. However, the use of antenna arrays to regulate both the electric near-field enhancement factor and area has rarely been reported. In this paper, a novel modified bow-tie (MBT) antenna array is proposed for better near-field enhancement performance in terahertz (THz) regime. Using commercially available high frequency structure simulator (HFSS), the dimensions of the MBT antenna array, including gap width, arm length, array period, and substrate thickness, are optimized to improve electric near-field enhancement performance in terms of higher factor, larger area, more controllable peak frequency, and wider 1-dB bandwidth. The as-optimized MBT and bow-tie (BT) THz antenna arrays are fabricated on quartz substrate via lithography and lift-off process. The normalized transmittances of the MBT and BT antenna arrays are characterized by THz time-domain spectroscopy (THz-TDS) and compared with the corresponding simulated near-field enhancement factor and normalized transmittance. The results indicate that the MBT antenna array outperforms the BT antenna array with a three-fold increase in near-field enhancement area and a 66.7% wider 1-dB bandwidth, and therefore can be used to enhance detection sensitivity and sensing accuracy in weak terahertz environment.

Design of Bowtie Antenna With Rounded Edge and Middle-Sliced Modifications for UHF Partial Discharge Sensor

Partial Discharge (PD) detection using ultra-high frequency (UHF) method has been proven as more noise-resistant in GIS condition monitoring, compared to the conventional PD detection methods, where the common noise frequency range such as in the power plants is below UHF frequency range. However, noise in UHF range may occur at certain conditions. Thus, UHF sensor with high sensitivity is necessary to detect PD-induced electromagnetic wave in UHF range. This paper discusses the modified design of a bowtie antenna as UHF sensor and its performance in detecting PD in the air. The modification method is conducted through simulation using antenna design software, resulting in curved-edge and middle sliced bowtie antennas. The designed bowtie antenna has wider bandwidth of above 300 MHz, reflection coefficient lower than -10 dB, and the voltage standing wave ratio (VSWR) less than 2. During initial design, the antenna geometry including gap distance, wing radius, and flare angle are adjusted to obtain the optimum antenna characteristics. The final designed sensor is then fabricated on a printed circuit board (PCB) with FR4-epoxy substrate material and tested using Vector Network Analyzer (VNA). Furthermore, the modified antennas are also tested in the high voltage laboratory to detect PD in needle–plane electrode. The experiment results show that both modified bowtie antennas can successfully detect the PD signal with correct phase patterns, and that the middle-sliced modified bowtie antenna is more sensitive than the rounded edge modified bowtie antenna.

Performance analysis of electrically coupled SRR bowtie antenna for wireless broadband communications

This paper presents a broadband Bowtie antenna with metamaterial periodical structure for broadband wireless systems and emerging 5G communication frequency band. The modified Bowtie antenna operating from 4 to 6.8 GHz with electrically coupled split-ring resonator (ECSRR) unit cells are proposed and analyzed. In two element Bowtie antenna, the third tuning arms are included to improve matching in the proposed operating frequency band. Four different shaped electrically coupled split-ring resonator (triangle, elliptical, hexagon and pentagon) with negative permeability and negative permittivity metamaterial unit cells are proposed and their reflection properties are analyzed. The triangle shaped ECSRR have the broadband reflection phase property which can be used to enhance the gain of the Bowtie antenna. The 5 $$\times$$ 6 periodical ECSRR unit cell embedded with modified Bowtie antenna in FR4 epoxy substrate ( $$\epsilon _r$$ = 4.4, thickness = 1.6 mm, tan $$\delta$$ = 0.025) was designed and fabricated. The presented Bowtie antenna design achieves a wide impedance bandwidth of 50% from 4 to 6.8 GHz (S11 $$\le$$ $$-$$ 10 dB) and maximum gain of 5.75 dBi. The designed metamaterial periodical structure has the reflection bandwidth of 4–6 GHz within $$-$$ 90 $${^{\circ }}$$ to + 90 $${^{\circ }}$$ in reflection phase and zero degrees phase reflection at 5.5 GHz. The metamaterial embedded bowtie antenna achieves a maximum gain of 11.08 dBi at 5.5 GHz. By tilting the metamaterial periodical structure, the major lobe direction of the modified Bowtie antenna can also be tilted. The experimental results show that the major lobe of the antenna can be tilted 34 $${^{\circ }}$$ approximately for 30 $${^{\circ }}$$ tilting of metamaterial structure with maximum gain of 9.8 dBi.

Design of Notched Rounded Bowtie Antenna for Ultra-Wideband Communication Systems

In this paper, a modified bowtie antenna structure is proposed for Ultra-Wideband communication systems. This antenna is obtained by rounding and notching the edges of antenna arms. Antenna parameters for the designed structure are examined according to the restrictions specified by Federal Communications Commission. Thus, Return Loss (S11), Voltage Standing Wave Ratio (VSWR), gain, radiation pattern and impedance are observed in the 3.1 GHz - 10.6 GHz frequency range. Additionally, the effect of arm length and dielectric material on antenna performance are interpreted in the same range.According to obtained results, the proposed structure satisfies the bandwidth requirements for Ultra-Wideband systems. Gain and impedance variations are also in acceptable limits for Ultra-Wideband applications. The proposed antenna is analyzed through CST Microwave Studio program.

Polarisation‐sensitive sub‐terahertz‐wave detector implementing antenna‐integrated zero‐bias Schottky barrier diode

A polarisation-sensitive sub-terahertz-wave detector has been developed by integrating an InP/InGaAsP Schottky barrier diode and a modified bowtie antenna. The fabricated quasi-optical module could detect signals at frequencies ranging from 30 GHz to 1 THz. The measured sensitivities were 1080 V/W at 250 GHz, 250 V/W at 400 GHz and 86 V/W at 600 GHz for a zero-bias condition. The principal polarisation axis angle for signal detection was confirmed to be stable within ±1.5° in a frequency ranging from 80 to 600 GHz, while the degree of polarisation was more than 95%.

A Modified Bow-Tie Antenna for Improved Pulse Radiation

The analysis, design, and realization of a modified bow-tie antenna optimized for impulse ground penetrating radar (GPR) applications is described. The proposed antenna shows improved properties important for GPR, which include its compact size (in comparison with a conventional bow-tie antenna) and ability to radiate UWB pulses with increased amplitude and very small late-time ringing. A substantial increase in the amplitude of the transmitted pulse is achieved by utilizing radiation from discontinuities introduced by the resistive loading employed in the antenna to suppress late-time ringing. By choosing an optimal distance between the antenna's feed point and the location of the resistive loading, radiations that occur from the antenna's feed point and the mentioned discontinuities at the resistive loading will combine constructively in the boreside direction of the antenna. As a result, one will observe a substantial increase of the amplitude of the transmitted pulse in the boreside direction. Furthermore, an analytical expression describing approximate time-harmonic current distribution is derived to indicate an optimal resistive loading profile for the proposed antenna. Additionally, the traveling-wave current distribution of the antenna is theoretically analyzed to examine the applicability of the obtained time-harmonic expression for pulse excitation. It has been found that when the antenna is resistively loaded both the time-harmonic and traveling-wave currents decay to approach nearly the same value at the end section of the antenna. As the amount of current at the antenna ends corresponds to the level of reflection which occurs there, the derived expression is found to be useful to indicate an optimal loading profile for the proposed antenna. A theoretical model of the proposed antenna has been developed to perform numerical analysis using a modified NEC-2 code. In addition, an experimental verification has been carried out and both the simulation and experiment confirmed the improved properties of the proposed antenna.