Communications: radio wave antennas – Antennas – Microstrip
Reexamination Certificate
2000-03-15
2001-03-27
Phan, Tho (Department: 2821)
Communications: radio wave antennas
Antennas
Microstrip
Reexamination Certificate
active
06208299
ABSTRACT:
FIELD OF INVENTION
The present invention relates to an antenna arrangement for receiving and/or transmitting electromagnetic signals in at least two spaced-apart frequency bands, a first frequency band having a first centre frequency and a second frequency band having a second centre frequency, in particular a first centre frequency being substantially higher than said second centre frequency, comprising
a first set of antenna elements being operative in said first frequency band,
a second set of antenna elements being operative in said second frequency band, and
a feeding network arranged for feeding signals, in said first and second frequency bands, to said first and second set of antenna elements, repectively.
PRIOR ART
Such an antenna arrangement is previously known from, e.g., EP 0 433 255 B1 (COMSAT), a first array of radiating elements (a first set of antenna elements) having a first size and a second array of radiating elements (a second set of antenna elements) having a second size being larger than said first size. The first array of radiating elements operates in a first frequency band which is at least 1 GHz higher than the second frequency band.
There is a first feeding layer with a power divider for feeding signals in the higher frequency band to the first array of antenna elements and a second feeding layer with a power divider for feeding signals in the lower frequency band to the second array of antenna elements. The power dividing elements in the two layers are designed so as to minimize the radiation interaction between the two arrays as well as the coupling between the two power distribution networks.
However, the antenna elements of the first and second arrays are located in corresponding positions in the respective layers of the multi-layer structure of the antenna arrangement. So, in each of the two dimensions of the generally planar structure, the two arrays have basically the same geometrical length (as measured between the outermost antenna elements). Let us assume that the antenna arrangement is substantially vertically oriented. Then, it will transmit a generally horizontal lobe of radiation, and the vertical beam width of the transmitted lobe will be approximately proportional to the wavelength of the radiation and inversely proportional to the total length of the respective array in the vertical dimension. Accordingly, since the vertical lengths are basically the same, the beam width of the radiation in the higher frequency band will be much smaller than the beam width in the lower frequency band. If the higher frequency (in the first band) is about twice the lower frequency (in the second band), the beam width of the high frequency lobe will be only half of that of the the low frequency lobe.
SUMMARY OF THE INVENTION
The principal object of the present invention is to provide an antenna arrangement, of the kind stated in the first paragraph above, wherein the structure is such that the two lobes of radiation in said first and second frequency bands have substantially the same beam width.
This object is achieved in that
the antenna elements in the first set of antenna elements are arranged geometrically so that said first set has a first length in a first direction,
the antenna elements in the second set of antenna elements are arranged geometrically so that said second set has a second length in said first direction, and
said first and second lengths are substantially inversely proportional to said first and second centre frequencies
In this way, the beam width of the radiation lobe associated with the first set of antenna elements will be basically the same as the beam width of the radiation lobe associated with the second set of antenna elements.
An antenna arrangement according to the invention can be implemented in many ways within the scope of the appended claims. Preferably, the antenna elements are patch elements which can be easily included in a multi-layer structure, as is well-known in the art.
The antenna elements in the first set can be located at positions being different from those of the antenna elements in the second set, as long as the geometrical lengths, measured in said first direction, are inversely proportional to the centre frequencies. However, even more conveniently, a subset of the antenna elements in the first (high-frequency) set may be located at substantially the same positions as those of the antenna elements in the second (low-frequency) set. This can be easily implemented with antenna elements in the form of patches disposed in different layers of a substantially planar structure.
The first and second sets of antenna elements may be arranged in a substantially regular array extended in at least one dimension corresponding to said first direction, e.g., in a linear, preferably vertical row or in a rectangular planar array.
Advantageously, there is only one feeding network for feeding the signals in said first and second frequency bands, a filter means being provided for separating one of said frequency bands. The filter means may include a band stop filter or a diplexer.
Alternatively, the antenna arrangement may include two such feeding networks for feeding dual polarized signals, so as to obtain diversity in double channels being mutually orthogonal to each other.
REFERENCES:
patent: 4429311 (1984-01-01), Barewald
patent: 4691206 (1987-09-01), Shapter et al.
patent: 4870426 (1989-09-01), Lamberty et al.
patent: 5534877 (1996-07-01), Sorbello et al.
patent: 5831581 (1998-11-01), Keough
patent: 6091365 (2000-07-01), Derneryd et al.
patent: 0433255A2 (1991-06-01), None
patent: 2157500A (1985-10-01), None
patent: WO99/31757 (1999-06-01), None
Jonsson Stefan
Karlsson Dan
Lindmark Bjorn
Allgon AB
Jacobson Price Holman & Stern PLLC
Phan Tho
LandOfFree
Dual band antenna arrangement does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dual band antenna arrangement, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dual band antenna arrangement will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2523554