Topic
Reflective array antenna
About: Reflective array antenna is a research topic. Over the lifetime, 4366 publications have been published within this topic receiving 57884 citations.
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TL;DR: In this paper, the authors investigated spherical, disc, and half-disc antennas in the frequency and time domains with the objective of developing small planar versions of the antennas with omni-directional impulse response in azimuth and pulse duration of 0.5-0.65 nanoseconds.
Abstract: A report on an investigation of spherical, disc, and half-disc antennas in the frequency and time domains with the objective of developing small planar versions of the antennas. These antennas have an omni-directional impulse response in azimuth and pulse duration of 0.5-0.65 nanoseconds. In addition, the measured data show a reasonable peak received signal in a pulse communication link using two identical antennas.
41 citations
TL;DR: The main idea is to develop a (1×N)-ports device in which the weightings on output ports are applied by time-reversal operation, which is applied to realize a passive ultrawideband (UWB) phased-array radar for target imaging.
Abstract: In this letter, the feasibility of a new concept of passive antenna beamformer is investigated. The main idea is to develop a (1×N)-ports device in which the weightings on output ports are applied by time-reversal operation. The control of antennas weightings is then contained in the input waveform without the need of active components or external control signals. This approach is validated experimentally by radiation pattern measurement of a four-Vivaldi-antennas array, associated to a small reverberation cell beamformer. Finally, this concept is applied to realize a passive ultrawideband (UWB) phased-array radar for target imaging.
41 citations
01 Jun 1967
TL;DR: In this article, the two-antenna method is considered to be essentially an insertions-loss measurement (with many additional problems and sources of error), and this concept is used to derive a working formula that is suitable for high-accuracy gain measurements.
Abstract: To calibrate antennas for state-of-the-art field-strength measurements above 1 GHz, standard antennas are needed that have gain values known to within ±0.1 dB. Since this requirements exceeds the verified accuracy of calculated gain values, these standards must be established by making absolute gain measurements. The discussion primarily concerns absolute gain measurements for horn antennas by the two-antenna method. However, much of the discussion is pertinent to high-accuracy field-strength measurements in general. The two-antenna method is considered to be essentially an insertions-loss measurement (with many additional problems and sources of error), and this concept is used to derive a working formula that is suitable for high-accuracy gain measurements. The two most intractable problems-- insufficient antenna separation and multipath interference--are discussed in detail. Some important experimental details are included that have previously been overlooked or inadequately discussed, and it is concluded that previous error estimates of less than ±0.1 dB for horn-gain measurements have been somewhat optimistic. To facilitate the design and evaluation of high-accuracy gain measurements, some simple terms, concepts, and formulas are provided that are useful in analyzing multipath interference.
41 citations
TL;DR: In this paper, the authors assess the feasibility of miniature directive antennas based on an analysis of the physical limits of antenna directivity in general and in particular as a function of their compact dimensions.
Abstract: This paper presents the work carried out to assess the feasibility of miniature directive antennas. It is based on an analysis of the physical limits of antenna directivity in general and in particular as a function of their compact dimensions. A state of the art is done to identify and classify techniques to increase the directivity of compact antennas.
41 citations
TL;DR: It is found that the MFB architecture applied in C-band is a more realistic approach when compared to the SFB option, and is the key to get compact feed clusters that can be allocated in large and medium-size platforms.
Abstract: Nowadays, broadband satellites operating at Ka-band and providing high capacity (above 100 Mbps) are mostly based on single-feed-per-beam (SFB) antenna configurations. This antenna farm, using typically three or four reflectors to produce the full dual-band (Tx/Rx) multiple beam coverage, provides high performance but leaves no or little room on the spacecraft for other missions. Accommodation constraints and the desire of operators to maximize and diversify their revenues per satellite have led to several studies on innovative antenna solutions enabling to reduce the number of reflector apertures. Multiple-feed-per-beam (MFB) antenna configurations, using only two apertures, are currently under development for broadband missions at Ka-band. C-band is a more mature business and operators are contemplating the possibility to apply the benefits of multiple beam antennas (MBA) to this frequency band. Due to the lower operating frequency, accommodation constraints are even more stringent and although still scarcely discussed, MFB antenna configurations at C-band are clearly of interest. This paper presents investigations on this topic. In particular, it is found that the MFB architecture applied in C-band is a more realistic approach when compared to the SFB option. Beam Forming Networks (BFNs) with periodic structure is the key to get compact feed clusters that can be allocated in large and medium-size platforms. A new four color scheme compatible with a very compact MFB feed array architecture is introduced.
41 citations