A novel integration strategy of microstrip antenna and metasurface is proposed to achieve low-radar cross section (RCS) improved radiation performance simultaneously. Aimed at the applications in stealth cylindrical carrier, has a circular configuration, cells are closely arranged around patch concentric ring-type manner. Moreover, mode analysis method fully used analyze antenna's working mechanism guide optimization process. Owing addition metallic vias, original quasi-TM <sub...

In the conventional routes to obtain stealth array antennas, various techniques are used reduce radar cross sections (RCSs) of existing antennas based on experience-relying trial-and-error and time-consuming optimizations. To address issue, we propose reverse thinking, i.e., low scattering performance precedes radiation performance, present a universal definite route achieve low-RCS directly from metasurfaces rather than antennas. A specific design method is carefully elaborated illustrate...

In this letter, an ultrawideband and low-loss reconfigurable reflective metasurface element (RMSE) with 1-bit resolution is proposed. The design integrates a PIN diode the cross-bow-tie patch to achieve phase shift (180° ± 20°) from 6.75 11.25 GHz (50% relative bandwidth) using wideband techniques such as gradient parasitic shunting structure. structure significantly reduces current flowing through diode, effectively minimizing loss. Consequently, proposed achieves both ultrawide operating...

In this paper, a novel design method that integrates broadband agile radiation and controllable scattering performance in one surface is proposed for an active metasurface. Each unit cell of the metasurface incorporated with tunable devices, such as electronic or micro-electro-mechanical-system (MEMS) varactor, to obtain frequency spatial electromagnetic (EM) wave modulation. Besides, probe also adopted element so can function antenna once fed by transmitter. way, integrated low radar cross...

Conventional artificial magnetic conductor (AMC) suffers from the thick profile and narrow bandwidth in low‐frequency band. Incorporating varactors into a passive AMC can adjust working frequency dynamically broaden operating band range. This study investigates different incorporation methods of using equivalent circuit analysis method. By establishing whole configuration, frequency‐domain characteristics active (AAMC) are theoretically analysed. It reveals that parallel allows lowering...

Abstract The Tianwen-1 Mars entry vehicle successfully landed on the surface of in southern Utopia Planitia May 15, 2021, at 7:18 (UTC+8). To acquire valuable Martian flight data, a scientific instrumentation package consisting flush air data system and multilayer temperature-sensing was installed aboard vehicle. A combined approach applied entry, descent, landing trajectory reconstruction using all available obtained by inertial measurement unit system. An aerodynamic database covering...

The aerodynamic configuration of the Tianwen-1 Mars entry module that adopts a blunt-nosed and short body shape has obvious dynamic instability from transonic to supersonic speeds, which may bring risk parachute deployment. unsteady detached eddy cannot be accurately simulated by Reynolds-Averaged Navier-Stokes (RANS) model, while computational cost for direct numerical simulation (DNS) large (LES) is huge. It difficult implement these methods in coupled engineering calculation flow motion....

This communication presents a wide bandpass frequency-selective surface (FSS) based on aramid-paper honeycomb sandwich structures. The proposed FSS consists of 2-D planar array hexagonal rings and 3-D stepped impedance slotlines. structures are constructed printed circuit board (PCB); meanwhile, the achieved with silver paste circuit. Based even- odd-mode analysis method, equivalent models extracted analyzed to explain operating principles thickness 16.7 mm achieves passband 2.90–9.55 GHz...

A unidirectional frequency reconfigurable bow-tie antenna array (FRBAA) is presented. The employs four doubled-sided antennas as the radiating elements. By controlling states of PIN diodes mounted on radiators, three switchable operating bands can be achieved. In order to produce radiation patterns with low profile and good impedance matching in all bands, a tri-band artificial magnetic conductor (AMC) designed incorporated array. distance between layer AMC reflector only 0.032λ <sub...

A compact ultra-wideband (UWB) antenna with controllable notched bands is proposed for UWB communication applications. By etching co-directional complementary split ring resonator (CSRR) on the patch, dual are generated. The center frequencies of can be tuned independently by changing effective electrical length inner and outer CSRR, which achieved employing two varactor diodes. Furthermore, replacing diodes electronic switches, operate in different working status.

In this paper, a novel shared-aperture method of electromagnetic metasurface and antenna is proposed to obtain low radar-cross-section (RCS) performance. method, the low-RCS first designed, then combined with traditional based on technique. Besides, analysis corresponding local structure modification are also conducted ensure that has good radiation performance while reducing broadband RCS. Using dual-layer polarization rotation unit cell its working principle investigated by both...

A novel frequency notched ultra-wideband microstrip antenna with GSRR structure is proposed. The consists of a conventional fork-shaped radiation patch and split ring resonator in slot modified ground plane (GSRR). By introducing this resonator, the has good band-notched performance WLAN band 5-6 GHz. proposed successfully simulated, designed, measured showing broadband matched impedance 3.3-10.8 GHz for 10-dB return loss, except band.

A new frequency notched ultra-wideband microstrip antenna with embedded open stub is proposed. The consists of a conventional U shape radiation patch and modified ground plane. By introducing an open-circuit stub, band obtained. operation bandwidth the 2.35–11.2 GHz, in which 5.3 – 5.9 GHz has been achieved. Simulation results are confirmed via experiment, showing good performance making it advantageous for high speed wireless communication systems.

This paper performs numerical simulation on the decompression process of a Mars rover using FLUENT. The pressure differential between inside and outside resulting from changes in ambient rocket fairing is investigated. In terms simulation, PROFILE outlet boundary conditions are developed impacts settings, time steps, mesh density investigated to improve accuracy results. separate large module, small modules under two types pressures simulated. results show that largest module body less than...

<p indent=0mm>The high-speed circumlunar return and reentry capsule has a velocity of close to 11 km/s, it uses skip trajectory in the Earth’s atmosphere. Therefore, chemical non-equilibrium effect flow field around during its is more serious complex than that LEO capsules. This paper models with seven components calculate analyze mechanism rule effects on aerodynamic characteristics at altitude 60–80 km. The numerical method boundary conditions for solving mid-high are then discussed....

Power semiconductor devices are widely used and its DC parameters test equipment in great demand. This paper broke through the key technology of high pulsed current generating based on charging discharging with capacitor. High voltage source, big pulse constant source that can large constant, small a digital voltmeter, etc important parts power have been developed. Also measurement software for testing has Based above, equipments instrument developed successfully.

In retro-directive microwave power transmission (MPT) systems, background noise imposed by the transmitting array on pilot receiving decreases reception single-noise-ratio (SNR). Isolation between two arrays should be guaranteed to obtain accurate direction of arrival (DOA) pilot. The isolation requirement analysis method is proposed and specific cases investigated in this paper. This work helps define an appropriate MPT system design.

In order to analyze and improve the shielding effectiveness of coating or metallic mesh, it is necessary estimate equivalent complex permittivity multilayer materials based on 3D-eIectromagnetic field simulation model experiment results. A method presented calculate for equivalence. Firstly, material established. After process wideband plane electromagnetic wave transmission, magnitude phase response in frequency domain are obtained. Secondly, free space method, mesh can be solved under...

This letter presents a unidirectional frequency reconfigurable bow-tie antenna (FRBA) with three switchable operating bands covering Bluetooth, WiMAX, and WLAN bands. The reconfigurability is realized by changing the effective electrical length of radiator, which accomplished attaching six PIN diodes on arms. To produce radiation pattern low back level increased gain, while still maintaining low-profile structure, tri-band artificial magnetic conductor (AMC) designed placed underneath as...

A dual-polarization ultra-thin tunable AMC (TAMC) surface working in P/L bands is presented. The tunability achieved by parallelly inserting varactor diodes between patch and ground plane. characteristic of the TAMC theoretically analyzed establishing equivalent circuit model. Simulated results show that proposed has profile (0.0035λ) achieves wide bandwidth from 0.35 GHz to more than 2 GHz.