EP2015390A2

EP2015390A2 - 6-8.5 GHz antenna diplexer with two-level resonating cavities.

Info

Publication number: EP2015390A2
Application number: EP08008671A
Authority: EP
Inventors: Pietro Marchisio
Original assignee: Tvc Sas Di Vignano P & C; Tvc S A S Di Vignano P & C
Current assignee: Tvc Tecnologie Di Vigano' Paolo E C Sas
Priority date: 2007-06-22
Filing date: 2008-05-08
Publication date: 2009-01-14
Also published as: ITMI20071253A1; EP2015390A3

Abstract

A 6-8.5 GHz antenna diplexer comprises a central-symmetry body having resonating cavities arranged on two levels to reduce the size of the construction and to also exploit the vertical dimension.

Thus, the diplexer exploits to a maximum degree all the available volume and, the resonating cavity number and electric features being the same, allows to reduce the overall volume with respect to a conventional diplexer having resonating cavity arranged at a single level.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a 6-8.5 GHz antenna diplexer with two-level resonating cavities.
More specifically, the diplexer according to the present invention has been designed to be used in a frequency range from 6 to 8.5 GHz which is particularly, though not exclusively, suitable for applications in mobile and fixed telephonic radio bridge applications.
As is known, a diplexer is a three-gate construction, generally arranged between a transceiver and an antenna to connect to a same antenna gate the output gate of the transmitter and the inlet gate of the receiver, which operate on discrete frequency bands, separated by an intermediate non-used band.
Accordingly, a diplexer conventionally comprises two filters, that is a receiving filter and a transmission filter, usually of a band-pass type, for separating the transmitting signals from the receiving signal, and a connection structure for connecting the two filters to the antenna gate or port.
The characteristics of said filters will depend on the filter operating frequencies, their frequency band and on several electrical and mechanical characteristics, based on which said filters are selected.
For filters having operating frequencies in a range pr band from 6 to 8.5 GHz, coupled resonating cavities are conventionally used, whereas the connection to the antenna gate or port is usually made by a T-connection or junction.
In a prior coupled-resonating cavity filter, the coupling of the filter cavities is performed through openings (iris apertures) formed through the walls between adjoining cavities.
The above mentioned iris apertures can be designed with different configurations and sizes.
For example, said apertures may have the same width or the same height, but not both the same width and height, as the wall separating the cavities.
All operating combinations between the above two limits would be possible, and some thereof would be more advantageous than other.
The numberings related to the cavities and iris apertures shows how the signal is propagated from the input to the output of the filter, whereas from the output to the input, the signal will follow a decreasing numbering.

SUMMARY OF THE INVENTION

The aim of the present invention is to provide such an antenna diplexer having a very small size construction.
Within the scope of the above mentioned aim, a main object of the invention is to provide such an antenna diplexer the operating frequency of which can be adjusted through a very broad range and which, in particular, is adapted to be tuned to a frequency range from 6 to 8.5 GHz.
Another object of the invention is to provide such an antenna diplexer including a receiving and transmitting filter with a frequency band from 42 to 84 MHz, which can be easily obtained through the overall frequency range from 6 to 8.5 GHz.
Yet another object of the present invention is to provide such an antenna diplexer having a centrally symmetrical construction, with like outputs to the receiver and the transmitter, thereby allowing to use said diplexer independently from a high band receiver and a low band transmitter, or vice versa.
Yet another object is to provide such an antenna diplexer allowing to achieve a diplexer filter shift variable from 118 MHz (at 8 GHz) to 245 MHz (at 7 GHz) and adjustable in a frequency range from 6 to 8.5 GHz.
Yet another object of the invention is to provide such an antenna diplexer allowing to introduce transmitting zeros or nulls through the (iris) apertures or openings between non adjoining cavities, to increase the selectivity thereof.
According to one aspect of the present invention, the above mentioned aim and objects, as well as yet other objects, which will become more apparent hereinafter, are achieved by a 6-8.5 GHz antenna diplexer having two-level resonating cavities, said antenna diplexer comprising a main metal body, therein resonating cavities are formed and being closed at two sides thereof by closing covers, said resonating cavities being electromagnetically coupled to one another so as to form a transmitting bandpass filter and a receiving bandpass filter.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention will become more apparent hereinafter from the following detailed disclosure of a preferred, though not exclusive, embodiment thereof, which is illustrated, by way of an indicative, but not limitative, example in the accompanying drawings, where:

Figure 1 is a perspective view of the antenna diplexer according to the present invention, and specifically showing the two covers of the diplexer welded to the diplexer main body, as well as its flange and 90° coaxial connector;
Figure 2 is a cross sectional view substantially taken through the cross section plane II-II of figure 3;
Figure 3 is a side longitudinal cross-sectioned view of the diplexer according to the invention;
Figure 4 is a top plan view of the diplexer;
Figure 5 is a cross sectional view substantially taken through the cross-section plane V-V of figure 3;
Figure 6 is a further cross-sectional view of the diplexer, substantially cross-sectioned through the plane VI-VI of figure 7;
Figure 7 is another side view, opposite to that of figure 3, and also longitudinally cross-sectioned, of the antenna diplexer according to the present invention; and
Figure 8 is further cross-sectional view of the diplexer, substantially sectioned through the section plane VIII-VIII of figure 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the number references of the above mentioned figures, the antenna diplexer according to the present invention, which has been generally indicated by the reference number 1, comprises a mechanical diplexer body 2, coupled to an antenna, through a guide connection, constituted by a flange 3 and being coupled to the receiver and to the transmitter by a respective 90° coaxial connector, of which only one, generally indicated by the reference number 4, has been shown in the figures.
In this connection it should be apparent that it would also be possible to use vertical coaxial connectors and coupling flanges of different configurations or shapes.
The figures show, moreover, the adjusting screw 5 for adjusting the diplexer forming filters, the main body and the two covers welded to said main body.
In said main body 2 two steps 6, to each of which a connector is coupled, are arranged.
Said steps 6 also split the subject construction into two planes, indicated by P1 and P2, each of which contains the diplexer resonating cavities 7 forming two filters.
The number N of said cavities 7, or resonating elements, forming each of the bandpass transmitting and receiving filters, are distributed on the two planes of the antenna diplexer construction.
Due to the central symmetry of this construction, if N_P1 is the number of cavities on the top plane P1 and P_P2 is the number of resonating cavities on the bottom plane P2, then, we will have N_P1R = P_P2T and N_P2R = N_P1T, where the letters "R" and "T" respectively show the receiving bandpass filter and the transmitting bandpass filter.
More specifically, in the embodiment of the invention being disclosed, we have N = 6, with N_P1R ≠ N_P2R.
As shown, the adjoining resonating cavities on a same plane are electromagnetically coupled through iris apertures 9, whereas for connecting the adjoining resonating cavities on different planes, elliptical shape apertures or openings 8, formed through the wall separating P1 from P2, are used.
Thus, the above disclosed two-planes distribution of the resonating cavities increases the number of adjoining resonating cavities, since the required connections may be either horizontal connections on a same plane, or vertical connections on two planes.
In turn, this will facilitate the introduction of transmitting zeros or nulls, i.e. of connections or couplings between adjoining cavities, but the numbering of which is not in succession.
Even this could also be achieved by conventional filters on a single level, the present construction provides a greater freedom in selecting the locations of the transmitting zeros.
The antenna diplexer according to the present invention operates as thereinbelow disclosed.
The signal enters the receiving iris aperture 10 and is sent or conveyed to the receiving cavity 11, therefrom it is conveyed to the cavity 12 through the iris aperture 9.
Then, said signal will be directed from the cavity 12 to the cavity 13, of plane P2, through the aperture or opening 8 and, from said cavity 13 it will enter the adjoining cavity 14 through the iris aperture 9.
Then, the signal will be directed from the plane P2 cavity 14 to the plane P1 cavity 15, through the opening or aperture 8.
From said cavity 15, the signal will enter the iris aperture 9 and then the adjoining cavity 16, where a signal pick up connector, designed for conveying the signal to a receiving cable, is provided.
In a transmitting operation, the signal will follow a reverse or opposite path.
It has been found that the invention fully achieves the intended aim and objects.
In fact, the invention provides an antenna diplexer having a small size construction, together with a very broad frequency adjusting capability, since it can be tuned to a frequency range from 6 to 8.5 GHz.
The antenna diplexer according to the present invention comprises a receiving and a transmitting filter with frequency bands variable from 42 to 84 MHz, which can be achieved through the overall frequency range from 6 to 8.5 GHz.
Since the subject antenna diplexer has a central symmetry, the diplexer outputs to the receiver (RX) and those to the transmitter (TX) are the same, thereby allowing the antenna diplexer to be used independently from the high band receiver and the low band transmitter, or vice versa.
Moreover, the antenna diplexer filter shift or spacing can be changed from 118 MHz (at 8 GHz) to 245 MHz (at 7 GHz) and adjusted to a frequency range from 6 to 8.5 GHz.
Furthermore, the antenna diplexer according to the invention allows to insert transmission zero's to iris apertures between adjoining cavities, thereby increasing the diplexer selectivity.
Furthermore, the antenna mouth being symmetrical, its size will be very small thereby fitting the space made available at the input by the two filters.
In fact, the two-filter illuminating symmetrical input mouth, instead of using a conventional T-junction, provides a greater freedom in constructing the antenna diplexer, thereby perfectly fitting the arrangement of the diplexer filter inputs, in turn allowing to further reduce its volume.
In practicing the invention, the used materials, together with the contingent size and shapes, can be any, depending on requirements.

Claims

A 6-8.5 GHz antenna diplexer, characterized in that said antenna diplexer comprises two-level resonating cavities and a main metal body therein said resonating cavities are formed and being closed at two sides thereof by two closing covers, said resonating cavities being electromagnetically coupled to one another thereby forming a transmitting bandpass filter and a receiving bandpass filter.
A diplexer, according to claim 1, characterized in that said diplexer has a central symmetrically arrangement.
A diplexer, according to claim 1 or 2, characterized in that said diplexer comprises a receiving filter and a transmitting filter, said receiving and transmitting filters having frequency bands variable from 42 to 84 MHz, and being achieved through the overall frequency range from 6 to 8.5 GHz.
A diplexer, according to one or more of the preceding claims, characterized in that said diplexer filters have a shift or spacing from 118 MHz (at 8 GHz) to 245 MHz (at 7 GHz) and being adjustable to a frequency range from 6 to 8.5 GHz.
A diplexer, according to one or more of the preceding claims, characterized in that said diplexer comprises (iris) apertures between non adjoining cavities, thereinto one or more transmitting zero's can be introduced to increase the selectivity of said diplexer.
A diplexer, according to one or more of the preceding claims, characterized in that said diplexer has a size of substantially 177x35x27 mm.
A diplexer, according to one or more of the preceding claims, characterized in that said diplexer has a frequency adjusting range from 6 to 8.5 GHz.