Wide-Beam Power Gain Pattern Synthesis With Accurate Sidelobe Control for Phase-Only Linear Arrays

This paper focuses on the problem of maximizing the minimum power gain in a wide main lobe for an array antenna. To obtain the desired power gain pattern, current literatures solve the problem known as shaped beam pattern synthesis (SBPS) by setting the beam pattern expression as the cost function. The power gain in a certain direction of the array antenna is comprehensively decided by the array radiated power density and the total radiated power. Both these two parameters are affected by the selection of array elements' weights. However, the SBPS-based methods do not take the total radiated power into account. Therefore, the SBPS-based methods cannot obtain the power gain pattern directly, and the optimal power gain pattern, consequently, cannot be guaranteed. To overcome this deficiency, this paper maximizes the minimum power gain in the desired wide main lobe by directly setting the power gain expression as the cost function. Aiming at optimizing the cost function, this paper first sets up a power gain optimization problem which has concave form. Termed this optimization problem as the power gain pattern synthesis (PGPS) problem. The concave PGPS problem is then converted to a series of convex subproblems and an iterative algorithm is proposed to solve it efficiently. Solution to the PGPS problem is proven to be able to achieve higher minimum power gain in a desired wide main lobe than the results from the SBPS-based algorithms. Simulations are carried out with both linear array antenna and planar array antenna. Comparisons with the existed SBPS-based algorithms validate the effectiveness and advantages of the proposed PGPS-based algorithm. In addition, further improvement on suppressing the sidelobe level for the PGPS problem is discussed.

A technique is described for measuring the complete hemispherical power-gain radiation pattern of a 2.44-m diameter paraboloidal reflector antenna mounted atop a mobile small earth terminal operating at 7.5 GHz. Antenna power-gain data were measured versus azimuth and elevation angles with the earth terminal centered on a heavy-duty turntable flush with test range ground.Test site illumination was achieved with airborne transmitting antennas. Conventional and statistical power-gain patterns are presented for left-hand circular polarization and cross polarization. Results indicate that similar systems cannot rely upon orthogonal polarization to provide isolation or compatibility beyond the angular region of the main lobe.

Shaped beam pattern synthesis with desired nulling level and minimum sidelobe level

The GPS Equivalent Isotropically Radiated Power (EIRP), defined as the product of transmit power and antenna gain pattern, determines the directional radio frequency (RF) power incident on the Earth surface. EIRP is of great importance to the Level 1B calibration of the normalized bistatic radar cross section (NBRCS) of the Cyclone Global Navigation Satellite System (CYGNSS) mission. To address the uncertainties in EIRP, a ground-based GPS constellation power monitor (GCPM) system has been designed, built, calibrated, and operated to accurately and precisely measure the direct GPS signals. The calibration subsystem and low noise amplifier (LNA) are implemented on a PID (proportional–integral–derivative) controlled thermal plate with extremely stable temperature over the long term. The calibrated GCPM received power is highly repeatable and has been verified with DLR/GSOC’s independent measurements. The transmit power of the full GPS constellation is determined using an optimal search algorithm. Updated values for GPS transmit power have been successfully applied to CYGNSS L1B calibration and found to significantly reduce the PRN dependence of CYGNSS L1 NBRCS and L2 science data products, including the ocean surface wind speed and mean square slope (MSS). Additionally, a complementary technique of estimating the GPS EIRP has been designed using direct signal measurements from the CYGNSS zenith antenna to fully map all GPS transmitters. The CYGNSS zenith antenna measurements are demonstrated to be able to sample the transmit antenna gain pattern over the complete terrestrial service volume within a very short time. An absolute power calibration algorithm was designed using the CYGNSS GPS signal simulator (GSS) and CYGNSS Delay-Doppler Mapping Receiver (DMR) to convert the raw counts to received power in watts. By incorporating zenith antenna measurements, the uncertainty in GPS EIRP due to transmitter antenna pattern asymmetry can be reduced. The CYGNSS zenith antenna and receiver as a real-time GPS power monitor are also a powerful tool to capture any abrupt change in the GPS EIRP that may occur. The CYGNSS four-channel zenith signal, in combination with a yaw attitude correction algorithm, is used to retrieve the full transmit antenna pattern for the GPS constellation. The system design and absolute power calibration scheme of the GCPM are helpful to the future design and implementation of GNSS receiver systems. The calibrated GPS transmit power and full transmit antenna pattern will be useful to the system design, science investigation and engineering calibration of future GNSS reflectometry missions.

Today's world demands information transfer, this is even more important on the digital battlefield. Communication devices are not just for calling in status. Today radios are used for data transfer from geo-location to live video all send over ad-hoc agile networks. Manpack (MP) radios have been reduced in size while retaining many of their features. Reduction in radio size and battery size results in lower output power to maintain useful mission life. To compensate for the reduce output power, Harris RF Communications Division has introduced a new family of soldier worn antennas which significantly improves the voice range and data-handling capabilities. The performance of a 5-W handheld (HH) radio with a soldier worn antenna has been shown to obtain better range than a 10-W manpack radio with a blade antenna. This paper discusses the development of the soldier worn antenna family and the flexibility from the typical deployment to urban use with low-profile configuration to extended range deployment. Three numerical codes were used for simulation: NEC, HFSS and ADS. Each used for optimizing the antenna's parameters to obtain the desired impedance, current distribution, power gain, and radiation patterns. Validations of such results were obtained empirically in both controlled and field testing environments. A discussion of RF noise on the battlefield and how the soldier worn antenna design helps minimize its effects is also included.

A design of dual-band balanced antenna structure operating in the 700 and 2600MHz LTE bands is studied and investigated. The overall dimensions of the radiator are 50 × 18 × 7 mm^3 allowing it to be easily concealed within mobile handsets. A broad-band balun is designed and integrated with the antenna handset in order to provide the feeding network and perform the measurements of the antenna radiation performance. Prototypes of proposed antenna with and without balun are fabricated and verified. The simulated and practical results with and without the handheld effects in terms of reflection coefficient, power gain and radiation pattern, are studied and shown reasonable agreement.

Ant Lion Optimization algorithm to control side lobe level and null depths in linear antenna arrays

Realistic radio modeling is crucial for accurate simulation of wireless networks. This paper examines the effect of using directional antennas in real environments with non-trivial multipath effects. We find that the actual variation in signal strength as a function of antenna direction differs appreciably - sometimes dramatically - from what the antenna power (gain) pattern alone would suggest. We quantify and analyze this difference across several antenna types and environments, and provide a generalizable parametric model to support more realistic planning, simulation and analysis.

An Excitation-DRR Control Approach for Wide-Beam Power Gain Pattern Synthesis

This paper deals with the problem of minimizing the nulling level (NL) given the desired minimum power gain and the desired sidelobe level (SLL) via a wide-beam array antenna. Different from the traditional approaches which solve the shaped beam pattern synthesis (SBPS) problem, the paper tries to further suppress the NL by solving the power gain pattern synthesis (PGPS) problem. We firstly sets up the mathematical model of the discussed problem, and then its non-convex structure is transformed into convex one via approximation scheme. As a result, the formulated problem can be solved effectively with available solvers. Numerical examples are provided to validate the performance of the proposed algorithm by compared with the existing SBPS-based algorithm, which validate the the proposed algorithm is able to further suppress the NL more than 10 dB.

The pattern synthesis technique of antenna arrays has a wide range of applications in radar and communication systems, which is an important research direction in the field of smart antennas. In order to improve the optimization performance of pattern synthesis of linear antenna arrays, an optimization method based on the Modified RIME Optimization Algorithm (MRIME) is proposed. RIME is a new heuristic algorithm inspired by the condensation process of frost ice in nature, which has a unique update mechanism with strong convergence as well as randomization. In the present work, MRIME is used for optimal pattern synthesis of a linear antenna array (LAA). One part of the present study is to optimize the side lobe level by optimizing the antenna current amplitude while maintaining a uniform spacing; the other part is to optimize the antenna position while assuming a uniform excitation in the synthesis of a sparse LAA, where constraints are imposed on the spacing of the array elements and aperture length, and suppression of the side lobe level with the position of the zeros in the specified direction is also achieved. In this article, simulation experiments for uniform linear arrays as well as sparse linear arrays are presented in detail, and the results show that the MRIME optimization algorithm outperforms most of the existing evolutionary classes of optimization algorithms in optimizing the side lobe level. This illustrates the potential of utilizing the MRIME optimization algorithm for antenna arrays and various other electromagnetism-related challenges.

In this paper, the problem of maximizing the beamwidth with array antenna giving the desired minimum power gain in the wide-beam mainlobe is addressed. Termed this problem as Mainlobe BeamWidth Maximization (MBWM). This paper, by optimizing the gain pattern instead of optimizing the beam pattern, first sets up the mathematical model for the MBWM problem. It comes out that the MBWM problem is non-convex, hence cannot be solved effectively in polynomial time. To simplify the solving processes, the MBWM problem, thereafter, is converted into a series of power gain pattern synthesis (PGPS) problems. The bisection strategy together with the processing procedures for the PGPS problem are utilized to design an iterative algorithm to solve the MBWM problem. Numerical simulations compared with the existing methods which optimize the beam pattern are carried out.

Based on the Gram-Schmidt orthogonalization method utilized for pattern synthesis of linear array without constraints, side lobe levels constraints in certain angular region is proposed to implement pattern synthesis with broad nulls. The advantage of the simplified computation resulted from steering vector orthogonalization in unconstrained orthogonal approach is maintained, and the uniform or non-uniform linear array pattern synthesis can be realized by this method. The computational complexity of this method is smaller than iterative algorithm method’s. The experimental results show that the side lobe levels constrained orthogonal approach can fulfill linear array broad null pattern synthesis with less computational efforts.

Synthesis of arbitrarily shaped radiation patterns using linear antenna arrays has a significant importance in many applications. Many attempts based on analytical schemes are exerted for this purpose. However, these analytical methods are developed for specific problems, and usually synthesis of the radiation pattern is subject to only one restriction. On the other hand, optimization algorithms are utilized for more general problems. However, these algorithms require more computational time. In this letter, a new hybrid technique for synthesizing arbitrary-shaped radiation pattern using a linear array is developed. The algorithm is based on a combination between the method of moments (MoM) and the genetic algorithm (GA). The proposed algorithm is applied to synthesis of both symmetric and asymmetric radiation pattern distributions with minimum number of elements. Excellent agreement is obtained by comparison to other analytical and optimization techniques.

This study presents an analysis of the convex optimization applied to the synthesis of the radiation pattern for linear antenna arrays. This study emphasizes the application of the convex optimization for the array pattern synthesis considering the simultaneous elimination of several zones interferences, reduction of the level of power in two space zones densely populated by interferences, as well as the variation of these zones in terms of proximity-distance of the source of interest, variation of the size of the interferences zones and the number of zones within the radiation pattern. Simulation results are provided. These results define certain levels where the linear array could be exploited to achieve a maximum performance.