Novel antipodal ultra-wideband slot antenna with low cross-polarization performance

The miniaturized high-gain antenna is required in portable, ultra-wideband radar systems. However, the miniaturization, ultra-wideband and high gain often restrict each other in the antenna design. In this paper, a dual-polarized, double-slot, antipodal tapered slot antenna with a double-layer, dual-loop structure and novel slot edges is presented. The proposed magnetic dual-loop structure has the capacity to reduce the low cut-off frequency of the double-slot tapered slot antenna by weakening the resonance and coupling. In addition, the high gain, low sidelobe level (SLL), and low cross-polarization level are achieved in the boresight direction. A novel gradient slot profile is designed to improve the low-frequency directivity of the tapered slot antenna without affecting the matching. To feed the antenna elements, a kind of wideband, balun-divider structure is designed. The dual-polarized antenna is combined by two orthogonal elements in a cross configuration without galvanic contact or influence to performance. The measured results show that the impedance bandwidth of the proposed antenna is 0.6~4 GHz, and the maximum gain is 11 dBi. The isolation between the two antenna ports is better than 32 dB, and the cross-polarization discrimination (XPD) is better than 20 dB.

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Low Cross-Polarization Gaussian Tapered Post-Wall Slotline Antenna for Short Pulse Applications

International Journal of Antennas and Propagation ◽

10.1155/2017/4852709 ◽

2017 ◽

Vol 2017 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Hongxin Zhao ◽

Yufu Li ◽

Xiaoxing Yin

Keyword(s):

Frequency Band ◽

Short Pulse ◽

Characteristic Impedance ◽

Ultra Wideband ◽

Slot Antenna ◽

Wall Structure ◽

Impedance Bandwidth ◽

Cross Polarization ◽

Lower Frequency Band ◽

Polarization Level

A Gaussian tapered slot antenna based on post-wall structured slotline for improvement of cross-polarization for ultra-wideband applications is proposed and experimentally demonstrated. The antenna is composed of two pairs of Gaussian tapered slotline which have the same structure printed on both sides of the PCB, two metallic via arrays positioned along the slot edges, and two terminal resistors. The metallic via arrays are used to reduce the characteristic impedance of the conventional slotline which form a post-wall slotline and thus can be fed by a coaxial connector directly. More importantly, the balanced symmetrical post-wall structure ensures low cross-polarization levels of the antenna. The Gaussian tapered edges and the terminal resistors diminish reflected signal and thus can enlarge the bandwidth significantly. Good agreements between the simulated and the measured results have been observed. Results show that the proposed antenna exhibits a −10 dB impedance bandwidth from 1.5 GHz to 20 GHz, a maximum realized gain of 12 dBi, and the broadside cross-polarization level is averaged about −32 dB in the lower frequency band and −25 dB in the higher frequency band with a maximum value of −22 dB in the whole working frequency band.

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Wideband-Narrowband Switchable Tapered Slot Antenna for Breast Cancer Diagnosis and Treatment

Applied Sciences ◽

10.3390/app11083606 ◽

2021 ◽

Vol 11 (8) ◽

pp. 3606

Author(s):

Seonho Lim ◽

Young Joong Yoon

Keyword(s):

Breast Cancer ◽

Coupling Effect ◽

Breast Cancer Diagnosis ◽

Microwave Imaging ◽

Ultra Wideband ◽

Slot Antenna ◽

Pin Diode ◽

Time Frequency ◽

Switching Mode ◽

Meander Line

In this paper, a wideband-narrowband switchable tapered slot antenna (TSA) with a compact meander line resonator for an integrated microwave imaging and hyperthermia system was proposed. A compact meander line resonator, which exhibited band-pass characteristics and provided narrowband characteristics by using one PIN diode, was fabricated beneath the tapered slot of the wideband TSA to minimize the degradation of the wideband characteristics. Moreover, the electromagnetic energy was transferred to the meander line resonator with a coupling effect to ensure effective frequency switching. By adapting a PIN diode on the meander line resonator, frequency switching could be achieved. In this way, the proposed antenna could operate in a real-time frequency switching mode between the ultra-wideband (UWB; 3.1~10 GHz), which is used for microwave imaging, and the 2.45 GHz band (industrial, scientific, and medical, ISM band), which is used for microwave hyperthermia. Frequency and time-domain results proved the applicability of the proposed antenna to an integrated breast cancer detection and treatment system.

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Selectivity and in-band impedance enhancement of a compact slot antenna with defected ground structures

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078719000734 ◽

2019 ◽

Vol 11 (10) ◽

pp. 1010-1016

Author(s):

Hailong Yang ◽

Xiaoli Xi ◽

Lili Wang ◽

Yuchen Zhao ◽

Xiaomin Shi

Keyword(s):

Reflection Coefficient ◽

Impedance Matching ◽

Ultra Wideband ◽

Band Edge ◽

Slot Antenna ◽

Defected Ground Structure ◽

Pass Filter ◽

Low Pass Filter ◽

Uwb Antennas ◽

Low Pass

AbstractIn this study, a new ultra-wideband (UWB) band-edge selectivity antenna with a modified radiation slot using defected ground structure (DGS) is presented to obtain bandpass filtering reflection coefficient and gain performance. The well-designed DGS is designed on backside metallic of the substrate and can be seen as a low-pass filter that provides a good roll-off at a higher frequency. By connecting the DGS and the stepped slot and making them merge with each other, good cut-off property in the upper passband and better in-band impedance characteristics are obtained. Measured results show that the proposed design not only shows good band-edge selectivity in reflection coefficient and gain performance but also has a good impedance matching of −13.5 dB reflection coefficients and a good radiation efficiency of 90% in the operating frequencies. The measured bandwidth defined with the reflection coefficient less than −10 dB is from 3.1–11.2 GHz. Furthermore, the size of the filtering UWB antenna is 22 mm × 12 mm, which is smaller than many individual UWB antennas and UWB filters.

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