The Experts below are selected from a list of 37833 Experts worldwide ranked by ideXlab platform
Zhenli Dong - One of the best experts on this subject based on the ideXlab platform.
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broadband 1 3 couplers with variable splitting ratio using cascaded step size mmi
IEEE Photonics Journal, 2018Co-Authors: Ye Tian, Jifang Qiu, Zhuili Huang, Yingying Qiao, Zhenli DongAbstract:In this paper, we propose and fabricated a novel scheme of SOI-based 1 × 3 coupler with variable splitting ratio. The coupler consists of two cascaded MMI with different sizes, and a wide range of splitting ratios from 1:0.1:1 to 1:18:1 can be achieved by modifying the size of the first-step MMI. Using the structure of cascaded step-size MMI, this kind of device has a compact footprint of below 15 μm × 15 μm and simple fabrication process. Meanwhile, the simulation analyses prove that the proposed couplers have a large Operation Bandwidth above 60 nm and be robust to the fabrication errors. Couplers with several splitting ratios were fabricated and well measured. Based on the measurement results, the splitting ratios of fabricated couplers from 1:0.67:1 to 1:18:1 can be achieved, and stable performance with the transmission efficiencies above 80% can be maintained over 50 nm wavelength range, which is the largest Operation Bandwidth to the best of our knowledge.
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Broadband 1 × 3 Couplers With Variable Splitting Ratio Using Cascaded Step-Size MMI
IEEE Photonics Journal, 2018Co-Authors: Ye Tian, Jifang Qiu, Zhuili Huang, Yingying Qiao, Zhenli DongAbstract:In this paper, we propose and fabricated a novel scheme of SOI-based 1 × 3 coupler with variable splitting ratio. The coupler consists of two cascaded MMI with different sizes, and a wide range of splitting ratios from 1:0.1:1 to 1:18:1 can be achieved by modifying the size of the first-step MMI. Using the structure of cascaded step-size MMI, this kind of device has a compact footprint of below 15 μm × 15 μm and simple fabrication process. Meanwhile, the simulation analyses prove that the proposed couplers have a large Operation Bandwidth above 60 nm and be robust to the fabrication errors. Couplers with several splitting ratios were fabricated and well measured. Based on the measurement results, the splitting ratios of fabricated couplers from 1:0.67:1 to 1:18:1 can be achieved, and stable performance with the transmission efficiencies above 80% can be maintained over 50 nm wavelength range, which is the largest Operation Bandwidth to the best of our knowledge.
Ye Tian - One of the best experts on this subject based on the ideXlab platform.
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broadband 1 3 couplers with variable splitting ratio using cascaded step size mmi
IEEE Photonics Journal, 2018Co-Authors: Ye Tian, Jifang Qiu, Zhuili Huang, Yingying Qiao, Zhenli DongAbstract:In this paper, we propose and fabricated a novel scheme of SOI-based 1 × 3 coupler with variable splitting ratio. The coupler consists of two cascaded MMI with different sizes, and a wide range of splitting ratios from 1:0.1:1 to 1:18:1 can be achieved by modifying the size of the first-step MMI. Using the structure of cascaded step-size MMI, this kind of device has a compact footprint of below 15 μm × 15 μm and simple fabrication process. Meanwhile, the simulation analyses prove that the proposed couplers have a large Operation Bandwidth above 60 nm and be robust to the fabrication errors. Couplers with several splitting ratios were fabricated and well measured. Based on the measurement results, the splitting ratios of fabricated couplers from 1:0.67:1 to 1:18:1 can be achieved, and stable performance with the transmission efficiencies above 80% can be maintained over 50 nm wavelength range, which is the largest Operation Bandwidth to the best of our knowledge.
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Broadband 1 × 3 Couplers With Variable Splitting Ratio Using Cascaded Step-Size MMI
IEEE Photonics Journal, 2018Co-Authors: Ye Tian, Jifang Qiu, Zhuili Huang, Yingying Qiao, Zhenli DongAbstract:In this paper, we propose and fabricated a novel scheme of SOI-based 1 × 3 coupler with variable splitting ratio. The coupler consists of two cascaded MMI with different sizes, and a wide range of splitting ratios from 1:0.1:1 to 1:18:1 can be achieved by modifying the size of the first-step MMI. Using the structure of cascaded step-size MMI, this kind of device has a compact footprint of below 15 μm × 15 μm and simple fabrication process. Meanwhile, the simulation analyses prove that the proposed couplers have a large Operation Bandwidth above 60 nm and be robust to the fabrication errors. Couplers with several splitting ratios were fabricated and well measured. Based on the measurement results, the splitting ratios of fabricated couplers from 1:0.67:1 to 1:18:1 can be achieved, and stable performance with the transmission efficiencies above 80% can be maintained over 50 nm wavelength range, which is the largest Operation Bandwidth to the best of our knowledge.
Chengkuo Lee - One of the best experts on this subject based on the ideXlab platform.
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Investigation of geometric design in piezoelectric microelectromechanical systems diaphragms for ultrasonic energy harvesting
Applied Physics Letters, 2016Co-Authors: Qiongfeng Shi, Tao Wang, Takeshi Kobayashi, Chengkuo LeeAbstract:Acoustic energy transfer (AET) has been widely used for contactless energy delivery to implantable devices. However, most of the energy harvesters (ultrasonic receivers) for AET are macro-scale transducers with large volume and limited Operation Bandwidth. Here, we propose and investigate two microelectromechanical systems diaphragm based piezoelectric ultrasonic energy harvesters (PUEHs) as an alternative for AET. The proposed PUEHs consist of micro-scale diaphragm array with different geometric parameter design. Diaphragms in PUEH-1 have large length to width ratio to achieve broadband property, while its energy harvesting performance is compromised. Diaphragms in PUEH-2 have smaller length to width ratio and thinner thickness to achieve both broadband property and good energy harvesting performance. Both PUEHs have miniaturized size and wide Operation Bandwidth that are ideally suitable to be integrated as power source for implantable biomedical devices. PUEH-1 has a merged −6 dB Bandwidth of 74.5% wit...
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mems based broadband piezoelectric ultrasonic energy harvester pueh for enabling self powered implantable biomedical devices
Scientific Reports, 2016Co-Authors: Qiongfeng Shi, Tao Wang, Chengkuo LeeAbstract:Acoustic energy transfer is a promising energy harvesting technology candidate for implantable biomedical devices. However, it does not show competitive strength for enabling self-powered implantable biomedical devices due to two issues – large size of bulk piezoelectric ultrasound transducers and output power fluctuation with transferred distance due to standing wave. Here we report a microelectromechanical systems (MEMS) based broadband piezoelectric ultrasonic energy harvester (PUEH) to enable self-powered implantable biomedical devices. The PUEH is a microfabricated lead zirconate titanate (PZT) diaphragm array and has wide Operation Bandwidth. By adjusting frequency of the input ultrasound wave within the Operation Bandwidth, standing wave effect can be minimized for any given distances. For example, at 1 cm distance, power density can be increased from 0.59 μW/cm2 to 3.75 μW/cm2 at input ultrasound intensity of 1 mW/cm2 when frequency changes from 250 to 240 kHz. Due to the difference of human body and manual surgical process, distance fluctuation for implantable biomedical devices is unavoidable and it strongly affects the coupling efficiency. This issue can be overcome by performing frequency adjustment of the PUEH. The proposed PUEH shows great potential to be integrated on an implanted biomedical device chip as power source for various applications.
Gonul Turhan-sayan - One of the best experts on this subject based on the ideXlab platform.
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Metasurface Lens for Ultra-Wideband Planar Antenna
IEEE Transactions on Antennas and Propagation, 2020Co-Authors: Omer Yesilyurt, Gonul Turhan-sayanAbstract:In this article, an ultra-wideband metasurface lens is designed and integrated into an antipodal Vivaldi antenna (AVA) to improve its radiation directivity without affecting its efficiency and return loss characteristics. The metasurface lens consists of high permittivity metamaterial unit cells which resonate at frequencies far away from the Operation Bandwidth of 1–6 GHz. Electric field distributions of the antennas show that the near-field behaves more planar for the metasurface lens loaded AVA, as compared to conventional AVA. Both the original antenna and the newly proposed antenna are simulated, fabricated, and tested. The measurements are found in very good agreement with the simulation results. In the Operation Bandwidth of 1–6 GHz, the return loss is less than −10 dB for both antennas. As verified by far-field measurements, the metasurface loaded AVA has achieved higher gain in the Operation Bandwidth. Additionally, the half power beamwidth of the AVA is significantly reduced by the inclusion of the metasurface lens.
Zhuili Huang - One of the best experts on this subject based on the ideXlab platform.
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broadband 1 3 couplers with variable splitting ratio using cascaded step size mmi
IEEE Photonics Journal, 2018Co-Authors: Ye Tian, Jifang Qiu, Zhuili Huang, Yingying Qiao, Zhenli DongAbstract:In this paper, we propose and fabricated a novel scheme of SOI-based 1 × 3 coupler with variable splitting ratio. The coupler consists of two cascaded MMI with different sizes, and a wide range of splitting ratios from 1:0.1:1 to 1:18:1 can be achieved by modifying the size of the first-step MMI. Using the structure of cascaded step-size MMI, this kind of device has a compact footprint of below 15 μm × 15 μm and simple fabrication process. Meanwhile, the simulation analyses prove that the proposed couplers have a large Operation Bandwidth above 60 nm and be robust to the fabrication errors. Couplers with several splitting ratios were fabricated and well measured. Based on the measurement results, the splitting ratios of fabricated couplers from 1:0.67:1 to 1:18:1 can be achieved, and stable performance with the transmission efficiencies above 80% can be maintained over 50 nm wavelength range, which is the largest Operation Bandwidth to the best of our knowledge.
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Broadband 1 × 3 Couplers With Variable Splitting Ratio Using Cascaded Step-Size MMI
IEEE Photonics Journal, 2018Co-Authors: Ye Tian, Jifang Qiu, Zhuili Huang, Yingying Qiao, Zhenli DongAbstract:In this paper, we propose and fabricated a novel scheme of SOI-based 1 × 3 coupler with variable splitting ratio. The coupler consists of two cascaded MMI with different sizes, and a wide range of splitting ratios from 1:0.1:1 to 1:18:1 can be achieved by modifying the size of the first-step MMI. Using the structure of cascaded step-size MMI, this kind of device has a compact footprint of below 15 μm × 15 μm and simple fabrication process. Meanwhile, the simulation analyses prove that the proposed couplers have a large Operation Bandwidth above 60 nm and be robust to the fabrication errors. Couplers with several splitting ratios were fabricated and well measured. Based on the measurement results, the splitting ratios of fabricated couplers from 1:0.67:1 to 1:18:1 can be achieved, and stable performance with the transmission efficiencies above 80% can be maintained over 50 nm wavelength range, which is the largest Operation Bandwidth to the best of our knowledge.
