Antenna Electrical Performance Research Articles

Compensation of phased array antenna electrical performance based on improved genetic algorithm

Phased array antennas are frequently subjected to surface distortions due to environ-mental factors during operation. Such distortions can lead to a deterioration in the electrical performance of the phased array antenna. This study provides an in-depth analysis of the impact of array distortions on electrical performance indicators. An electronic compensation approach, employing an enhanced genetic algorithm, is proposed to mitigate the effects of these distortions. The conventional genetic algorithm has been augmented with an elimination mechanism to boost convergence. This method compensates for amplitude and phase by calculating each element's amplitude and phase of the excitation current, thereby enhancing the convergence performance. Simulations this approach, simulations of rectangular microstrip patch antennas are conducted to validate the effectiveness of this approach. The simulation outcomes reveal that the proposed method significantly improves the antenna's radiation pattern and all performance indicators, confirming its efficacy.

A geostationary orbit microwave multi-channel radiometer

The geostationary orbit microwave multi-channel radiometer has the advantages of high real-time performance and large coverage, which plays an important role in typhoon, strong precipitation detection, and medium-to-short-term meteorological/oceanic forecasting. However, due to the difficulty in engineering development of the payload, its application on-orbit has not yet been achieved at present. To satisfy the requirements of fine and quantitative application of satellite observation data, a geostationary orbit microwave multi-channel radiometer with a 10-m-caliber is developed, in which the spatial resolution at horizontal polarization is better than 24 km at 54 GHz. In geostationary orbit microwave multi-channel radiometer, a quasi-optical feed network covering nearly 28 frequency octave bands and ranging from 23.8 to 664 GHz is proposed to solve the technical problem of multi-frequency sharing in the system. Meanwhile, a high-precision reflector preparation method and a high-precision unfolding scheme are proposed, which are considered as a solution for the large-diameter reflector with a high maintaining surface accuracy. A high-precision antenna prototype with 0.54-m is developed, and the tests are performed to verify the key technologies, such as the preparation of high-precision grating reflectors at the micron level, high surface accuracy detection, and sub-millimeter wave antenna electrical performance testing. The results indicate that measured main beam efficiency of the 664 GHz antenna is better than 95.5%. In addition, the system sensitivity is greater than 1.5 K, and the calibration accuracy is better than 1.8 K, according to the results of an analysis of the multi-channel radiometer’s essential parameters and calibration errors.

Functional Damage Assessment Method for Preformed Fragment Warheads to Evaluate the Effect on the Phased-Array Antenna

Damage assessment of a small-weight precision-guided warhead to evaluate the effect on the performance of high-value vulnerable targets should focus on functional damage instead of physical damage. Developing a damage assessment model that considers target function attenuation as a damage criterion for warhead design and tactical application is of great significance. In this paper, an accurate mathematical description of a preformed fragment warhead is provided. The failure of phased-array antenna elements in different initiation conditions is predicted by a shot-line model and spatial coordinate mapping. A real-time co-simulation model of the explosion damage field and the phased-array antenna electrical performance is developed and the effective damage modes are obtained through multi-condition simulation and electrical performance parameters analysis, which has more tactical application value than the structural damage assessment method with equivalent targets and the electrical simulation in artificial or random phrased-array-element failure conditions.

Structural-Electromagnetic-Thermal Coupling Technology for Active Phased Array Antenna

Active phased array antenna (APAA) is a representative of complex electronic equipment, and it plays significant roles in scenarios such as battlefield situation perception, aviation guidance, and communication. It has become the core equipment in land, navigation, and aeronautical applications. With the continuous improvement of technical changes and military requirements, the working frequency band, pointing accuracy, gain, and low sidelobe level of APAA increase, and the multi-disciplinary design contradiction between antenna electrical performance and structure and temperature becomes increasingly prominent. As a result, the electrical performance of APAA in service is prone to be affected by the external complex environments. The structural-electromagnetic-thermal (SET) coupling problem has become a key problem restricting the development of APAA. This paper has summarized the structural features and environmental loads of advanced APAA on different platforms and provided design basis and principle for antenna designer. And then the SET coupling theory of APAA has been introduced, which can be applied in both the design and manufacturing stage, as well as the performance control technology in service environment of APAA. This theory helps to analyze the impact of environmental factors, such as antenna structure deformation, radome high-temperature ablation, and feed errors, on the antenna's performance. For 128 × 768 spaceborne array antenna, in the range of 25∼85°C, the gain of antenna decreases with the increase of operating temperature and decreases by 0.015 dB with each increase of 1°C. The key design parameters in the fields of antenna manufacturing accuracy, efficient heat dissipation, and lightweight design are also analysed; for 32 × 32 rectangular planar phased array antenna, the gain of antenna decreases by 2.715 dB when the random error of installation position in x, y, and z direction reaches 1/10 of the wavelength. In addition, condition monitoring, displacement field reconstruction, and electrical performance compensation of APAA have also been touched to help engineers maintain and guarantee the antenna performance throughout its life cycle. Finally, the future research direction of SET technology of APAA has been discussed, and SET technology is extended to more fields such as antenna parameter uncertainty, high-frequency circuit electronics manufacturing, and electronic equipment performance guarantee.

Investigation of the Performance of Antenna Array for Microwave Wireless Power Transmission Considering the Thermal Effect

This paper investigates the thermal effect on the electrical performance of transmitting antenna array for microwave wireless power transmission through simulation and experiment. Firstly, the effect of temperature on the antenna electrical performance is sorted out as the thermal drift of performance (TDP) of transmitter module and the thermal deformation of structure (TDS) of antenna array. An analysis model reflecting the thermal effect is developed. Then, for the TDP of transmitter module, an experiment platform is built to measure the modules performance at different temperatures, and a TDP curve is constructed using interpolation based on the experimental data. Moreover, the thermal and structural analysis of the antenna array is performed to obtain the temperature distribution and the TDS of the antenna. Finally, the effects of TDP and TDS on the electrical performance of the antenna array are simulated numerically and verified experimentally.

Active Compact Wearable Body Area Networks for Wireless Communication, Medical and IoT Applications

The development of compact wearable antennas and transceivers for communication, IoT (Internet of Things), and biomedical systems will be presented in this paper. Development of Compact efficient wearable antennas is one of the major challenges in development of wearable communication, IoT, and medical systems. The main goal of wireless body area networks (BANs), WBANs, is to provide continuously medical data to the physician. Body area network (BAN) antennas should be flexible, lightweight, compact, and have low production cost. However, low efficiency is the major disadvantage of small printed antennas. Microstrip antennas resonant frequency is altered, due to environment conditions, different antenna locations, and different system operation modes. These disadvantages may be solved by using compact active and tunable antennas. A new class of wideband active wearable antennas for medical applications is presented in this paper. Amplifiers may be connected to the wearable antenna feed line to increase the system dynamic range. Small lightweight batteries supply the bias voltage to the active components. An active dual polarized antenna is presented in this paper. The active dual polarized antenna gain is 14 ± 3 dB for frequencies ranging from 380 to 600 MHz. The active transmitting dual polarized antenna output power is around 18 dBm. A voltage-controlled diode, varactor, may be used to control the antenna electrical performance at different environments. For example, an antenna located in patient stomach area has VSWR (Voltage Standing Wave Ratio) better than 2:1 at 434 MHz. However, if the antenna will be placed on the patient back, it may resonate at 420 MHz. By varying the varactor bias voltage, the antenna resonant frequency may be shifted from 420 to 434 MHz. An ultra-wideband passive and active printed slot antenna may be employed in wideband wearable communication systems. The active slot antenna gain is 13 ± 2 dB for frequencies from 800 MHz to 3 GHz.

Suppressed back‐lobe substrate‐integrated waveguide slot array antenna for X‐band

Utilising an array that is constructed by combining short-ended stubs and microstrip lines, a planar-choke structure is presented. By locating the proposed chock structure on the bottom of the substrate-integrated waveguide slot array antenna, undesired spillover current and edge diffractions are removed. Measurement result show that in the operational bandwidth the backward radiation is reduced by more than 20 dB and the side-lobe level is improved by 5 dB without degrading of the antenna's electrical performance.

A dual-band internal antenna with a parasitic patch for mobile handsets and the consideration of the handset case and battery

This letter proposes a compact internal antenna of the modified planar inverted F antenna (PIFA) type with a parasitic patch. It also considers the influences of the handset case and battery. A low-profile design is implemented on both the top and bottom sides of the FR-4 substrate. The proposed antenna, with the small size of 27.5/spl times/12/spl times/7 mm/sup 3/, can be easily placed in the actual handset. The measured bandwidths of the proposed antenna with handset case and battery ( VSWR<2 ) can cover 140 MHz (1740-1880 MHz) in the Korean personal communication service (KPCS) band and 90 MHz (2400-2490 MHz) in the Bluetooth band. Numerical simulation and experiment results of antenna electrical performance are investigated by considering the antenna, the phone case, and the battery.

A 5-frequency millimeter wave antenna for a spaceborne limb sounding instrument

Several spaceborne Earth observation missions such as the European Space Agency's (ESA) atmospheric chemistry instruments Millimeter wave Acquisitions for Stratosphere/Troposphere Exchange Research (MASTER), Soprano or Piramhyd require the development of complex millimeter and submillimeter wave range spectroradiometers. These instruments place stringent requirements on antenna electrical performance due to the low-noise signal levels and the high-vertical resolution involved. This paper focuses on the electromagnetic (EM) design and analysis of a 2.2-m diameter Cassegrain antenna operating in 5-frequency bands between 200 and 500 GHz. The primary feed network is an essential part. It has to provide not only the low-loss frequency separation of the bands but also the antenna illumination with nearly perfect amplitude and phase patterns for high-beam efficiency. Quasi-optical techniques are extensively used for the overall antenna design and focal plane demultiplexer breadboarding and testing.

Antenna performance evaluation with reflector distortion data using Akima's interpolation scheme

As multibeams begin to be used in satellite communication, the satellite-borne antennas have become larger. Hence, development of an antenna with a large aperture with a lightweight and high surface accuracy is being carried out. Unlike conventional small antennas, this antenna experiences a large thermal deformation due to severe environmental conditions on the geostationary orbit. In addition, a large deformation due to gravity occurs in the performance confirmation test on the ground. In the development of such a large antenna, it is indispensable to develop a method to appropriately evaluate the change of electrical performance by the deformation. In this paper, an antenna characteristic computation method is presented which can compute the radiation characteristics of the reflector surface for arbitrarily deformed shapes. The present method uses Akima's interpolation scheme for the deformation data so that data needed for computation of the radiation characteristics are obtained and highly accurate computations are realized. The analysis results of the deformation of the reflector surface of a reflector by a general-purpose structural analysis program (NASTRAN) is linked to the present computation method so that the variation of the antenna electrical performance by deformation is obtained and the results of the present method are presented. Further, it is shown that the measured antenna characteristics and the numerical results of the electrical performance by the reflector surface measurement data agree well. Hence, the present antenna characteristic computation method is extremely useful for the evaluation of the antenna characteristics.