Compensation of distorted offset parabolic reflector using an array feed

Cherrette, A.; Lam, P.; Lee, S.; Acosta, R.

doi:10.1109/aps.1986.1149709

Cited by 4 publications

(2 citation statements)

References 3 publications

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“…Variations from the designed shape lead to antenna performance degradation, compromising the antenna radiation pattern. The shape distortions can often be dynamically corrected with onboard actuators [ Lang and Staelin , 1982; Lawson and Yen , 1988; Clarricoats and Zhou , 1991; Pino et al , 2006] or feeding arrays [ Acosta , 1986; Cherette et al , 1986; Rahmat‐Samii , 1990; Bailey , 1991; Smith and Stutzman , 1992] but it is essential to determine exactly where and how great the distortions are.…”

Section: Introductionmentioning

confidence: 99%

Reflector antenna distortion determination: An iterative‐field‐matrix solution

2008

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[1] The idealized shapes of satellite reflector antennas are often distorted once they are placed in orbit. The performance of such antennas can be improved by identifying the locations and amount of their surface distortions and then by correcting them using active surface distortion or array feeding. This work presents a method to determine the required discrete surface distortions to correct errors. The algorithm starts by discretizing the entire reflector surface into triangular patches, then by determining the linear relationship between the local distortion and the difference between distorted and undistorted far-fields patterns. A linear system of equations with discrete distortions as unknowns results when this scattered field is sampled at specific observation points. Singular Value Decomposition combined with Tikhonov regularization, is used to solve for the set of distortions, which are translated into a physically realizable continuous surface by projecting onto a Polynomial-Fourier-Series basis. The later scheme is iteratively repeated in order to minimize the residual error. The method has been applied successfully to determine thermal/gravitational distortions on a reflector antenna, with up to 97% accuracy in tenth iteration.

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Section: Introductionmentioning

confidence: 99%

Reflector antenna distortion determination: An iterative‐field‐matrix solution

2008

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“…In this sense, once the determination of the reflector shape distortion is completed, the correction of the surface shape distortion is proposed to be done by actuators in [15][16][17][18] and the compensation of its impact on the resulting far-field pattern by using feed arrays as described in [19][20][21][22][23], but it is important to previously determine how distorted the reflector surface is and its impact on the antenna performance.…”

Section: Introductionmentioning

confidence: 99%

Analytical expressions for the evaluation of gravity distortion impact on the antenna efficiency applied to large antenna uplink arrays

Natera

Rodríguez-Osorio

Ariet

et al. 2018

IET Microwaves, Antennas & Propagation

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We present analytical expressions for the evaluation of the antenna efficiency loss due to the gravity distortion on large reflector antennas from 6 to 35 m diameter at X and Ka bands with a lack of usual complexity. These analytical expressions can be used to evaluate the gain reduction versus the maximum deviation of the rim of the reflector due to the gravity distortion extending the model proposed by JPL to other antenna diameter in the range of 6 to 35 m. These expressions were compared with the empirical model for gravity evaluation presented by the Jet Propulsion Laboratory for the DSN antennas obtaining a good match between both models. This is useful to specify the maximum distortion due to the gravity for antenna system design level. For this, a five steps procedure is presented starting with the estimation of the antenna efficiency reduction based on the analytical expressions as a function of the maximum gravity distortion, the antenna size and frequency band and concluding with the estimation of the gain of a single antenna as a function of the elevation angle. The case study is focused on error analyses for large antenna uplink arrays at X and Ka band.

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Case study of active array feed compensation with sidelobe control for reflector surface distortion

Acosta

Zaman

Bobinsky

et al.

1988 IEEE AP-S. International Symposium, Antennas and Propagation

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The feasibility of electromagnetically compensating for reflector surface distortions has been investigated. The performance characteristics (gain, sidelobe levels, etc.) of large communication antenna systems degrade as the reflector surface distorts mainly due to thermal effects from a varying solar flux. The techniques descibed in this report can be used to maintain the design performance characteristics independently of thermal effects on the reflector surface. With the advent of monolithic microwave integrated circuits (MMIC), a greater flexibility in array-fed reflector system design can be achieved. MMIC arrays provides independent control o f amplitude and phase for each of many istics (x,y,z, its first and second derivatives) under distortion condition are known.

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Compensation of distorted offset parabolic reflector using an array feed

Cited by 4 publications

References 3 publications

Reflector antenna distortion determination: An iterative‐field‐matrix solution

Reflector antenna distortion determination: An iterative‐field‐matrix solution

Analytical expressions for the evaluation of gravity distortion impact on the antenna efficiency applied to large antenna uplink arrays

Case study of active array feed compensation with sidelobe control for reflector surface distortion

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