Single-Port Percutaneous Nephroscopy combined with GreenLight Laser in Simple Renal Cyst.

OBJECTIVE: To explore the therapeutic effect of percutaneous nephroscopy combined with Green Light laser on simple renal cyst. METHODS: A retrospective analysis was conducted to review the clinical data, surgical procedures, intraoperative bleeding, postoperative adverse reactions, and length of stay of 32 patients who had been admitted to Affiliated Hospital of Hebei University from January 2018 to February 2019. All patients had been diagnosed with simple renal cyst by imaging examination and met the surgical indications for single-port percutaneous nephroscopy combined with GreenLight laser for unroofing and decompression of the renal cyst. Among the 32 patients, there were 18 males and 14 females, with 15 cases on the left and 17 on the right. The patients aged 38 to 62 years old, with an average of 45 years old. Thirteen cases were hospitalized mainly due to complaint of lumbar pain, and 19 cases were admitted after a renal cyst was found by physical examination. The diameter of the cyst ranged from 4.2 to 9.1 cm, with an average of 6.1 cm. A percutaneous nephroscopic channel was established during the surgery. Once a nephroscope was placed into the cyst, GreenLight laser (energy of 80W) was used to remove the free cyst wall 0.3cm from the renal parenchymal margin under direct vision. After the incision margin was observed with no obvious exudation under microscope, the cyst wall was removed through the channel and sent for pathological examination. A drainage catheter was placed near the cyst cavity. RESULTS: All the 32 patients were successfully operated, without transition to laparoscopic and open surgery. The operations took 30 to 62 minutes, with an average of 45 minutes. The intraoperative bleeding ranged from three to 14 ml, with an average of 10 ml. No adverse events such as postoperative infection, fever, or active bleeding occurred. The drainage catheters were removed one to three days after operation, with an average of 1.5 days after operation. The drainage volume was 20 to 55 ml, with an average of 35 ml. No obvious liquid extravasation was seen in all cases. The length of stay after operation ranged from three to five days, with an average of 3.5 days. Postoperative pathological reports all suggested renal cyst wall. The patients were followed up for six months, and no cyst recurred. CONCLUSIONS: Single-port percutaneous nephroscopy combined with Green Light laser could provide significant clinical effect in treating simple renal cyst with minimal trauma.

A dielectric embedded reflectarray for high-power microwave application.

To solve the problem of the large axial size of high-power microwave (HPM) reflectarray antenna and difficulty in vacuum packaging, a dielectric is introduced in the design of the antenna element. On this basis, a dielectric embedded metasurface reflectarray antenna (DEMRA) with high power handling capacity and wide-range beam scanning capability is proposed and fabricated. Compared with traditional HPM antennas, the DEMRA does not need to be sealed and can work directly in open-air conditions. The DEMRA can realize free regulation of the radiation beam within a cone angle of 90° and has a power handling capacity of 1 GW/m2. As verification, a protype working at 10 GHz is fabricated and low-power experiments are carried out. Experimental results are consistent with the simulation, proving that the DEMRA has a bandwidth exceeding 600 MHz. During the scanning process, the aperture efficiency is always higher than 48.98%, and the side lobe level remains below -15 dB. At the same time, the cross-polarization component is less than -15 dB, while the main lobe-axis ratio remains within 4.5 dB, confirming its beam scanning capability.

Design and experimental demonstration of a beam scanning lens antenna.

A beam scanning antenna based on an all-metal lens is presented for high-power microwave (HPM) application in this paper. This design includes a feed antenna and two layers of different all-metal lenses, whose prototypes operating at 14.25 GHz have been successfully designed and fabricated with an aperture radius of 300 mm. A full transmission phase range of 360° can be achieved with a transmission efficiency of over 99% by rotating the cross-slot on the lens elements. The results of the low-power tests depict that the designed antenna can realize a beam scanning range of 120° revolving cone angle with the side lobe below -10 dB and the reflection coefficient less than -16 dB. The high-power tests demonstrate that the power handling capacity of the antenna is higher than 350 MW in sulfur hexafluoride (SF6). In addition, both the designed lenses have a bandwidth of more than 100 MHz. All the merits show that our designed all-metal lens antenna has a great potential to be applied in HPM systems.

A double-layer wideband radial-line waveguide power divider/combiner for high-power microwave application.

A compact double-layer wideband 1:60 power divider/combiner based on a radial-line waveguide is designed and investigated for high-power microwave (HPM) applications. Compared with other HPM radial-line power dividers, the proposed power divider is smaller and more compact. The power divider is miniaturized by the double-layer method, and the wideband characteristic is realized by a specially designed wavy disk. Moreover, it can divide the microwave energy into 60 output ports equally by symmetrical design. As for simulation, in the range of 1.64-3.6 GHz, the voltage standing-wave ratio is below 2 (the relative bandwidth is 76%) and the return loss reaches -44 dB at 2.1 GHz. Additionally, a prototype is fabricated and the wideband performance from 1.6 to 2.6 GHz is verified by an existing wideband antenna array. Furthermore, filled with SF6 (0.3 MPa), the theoretical power handling capacity is more than 200 MW and the device works steadily in HPM tests under the condition of 140 MW. To sum up, the compact power divider/combiner has important application potentials in HPM fields.

A compact high-power microwave TM01-TE01 mode converter.

In circular waveguides, the TE01 mode has the lowest transmission loss, which is very suitable for long-distance transmission of high-power microwaves (HPMs). The output mode of HPM sources is mainly the TM01 mode; however, there are few research studies on mode converters of TM01-TE01. In this paper, a high efficiency HPM TM01-TE01 mode converter is designed; compared with the traditional TM01-TE01 mode converters, the structure of the mode converter is compact and easier to process. It is mainly composed of an input circular waveguide, a tapered rectangular waveguide, a 90° bent rectangular waveguide, and an output circular waveguide. A prototype with a center frequency of 2.4 GHz is fabricated and HPM experiments are carried out. The transmission efficiency of this device reaches 99.8% in the simulation, and the measured transmission efficiency is more than 98%. Additionally, the measured power handling capacity is more than 1 GW, which is consistent with simulation. This design has important reference significance for the design of long-distance power transmission devices and HPM mode converters.

Designs and experiments of a novel compact E-shaped wideband planar antenna array for high-power microwave application.

A novel compact E-shaped wideband planar antenna array (CEWPA) is designed and fabricated for high-power microwave (HPM) application. The CEWPA is a kind of planar antenna and it has a lot of advantages such as low profile, wideband, high efficiency, easy to manufacture, and light weight. Compared with traditional planar antenna arrays, it overcomes the disadvantage of low power capacity through special metal structure designs. The CEWPA consists of 60 antenna elements and achieved miniaturization by an innovative array layout. In addition, it has reached a relative bandwidth of 33% (VSWR < 2) at a center frequency of 2.1 GHz in simulation and over 20% in experiment. On the other hand, the measured gain at the cold test is greater than 20 dB in the whole bandwidth while the radiation patterns are in agreement with the simulation. In addition, excited by nanosecond level pulses, the power capacity of the whole system is more than 140 MW in a high-power test.

An aperture coupled microstrip antenna array for high power microwave application.

A three-layer aperture coupled microstrip antenna array (ACMA) is designed and fabricated for wideband high-power microwave (HPM) application, which has not been reported in the field of HPM. In this paper, the proposed antenna array overcomes the disadvantage of low power capacity of traditional microstrip antenna arrays. Moreover, based on the H-shaped aperture coupled structure, it enhances the relative bandwidth up to more than 50%. Compared with traditional HPM antennas, it has advantages of being low-profile (less than 0.2λ), wideband, lightweight, and easy to manufacture. The proposed antenna array consists of 60 elements; each element has four aperture coupled patch antennas fed by a four-way microstrip line power divider. In order to realize the modular design, the antenna array is divided into 10 identical modules; benefiting from this design, machining and assembling become easier. Additionally, cold tests and high-power tests are carried out, and the experimental results show that the ACMA achieves a relative bandwidth of 51.2% for voltage standing-wave ratio < 2 from 1.52 to 2.57 GHz. Consistent with simulation results, the measured gain is more than 28.8 dB in the whole bandwidth and it reaches a maximum of 32.1 dB. Finally, the high-power tests show that the power capacity of the proposed ACMA is greater than 140 MW, which proves the feasibility of the design in wideband HPM application.