The present subject matter relates to phase shifter and more specifically to electro-mechanical phase shifter. This phase shifter can be used within mobile radio antennas, but also to any Radio Frequency (RF) device requiring a phase shift
The technical key requirements of Base Station antennas for radio communication applications are high gain, good purity of horizontal-plane (H-plane) and vertical-plane (V-plane) patterns. Gain and vertical-plane patterns requirements (i.e. tilt value, control of lobes, capability of null filled) are mainly function of the antenna length and are controlled via the feeding network of the antenna.
Variable Electrical Tilt (VET) antennas have capability of tilt variation, i.e. of main lobe position variation versus the horizon. The adjustment of this tilt position may be achieved per several techniques applied to the antenna feeding network, using active and/or passive devices. The main component needed to achieve such tilt variation is a phase shifter device.
The present application deals with passive phase shifter devices, particularly the family of phase shifters using dielectric materials. At least two “dielectric materials” have to be considered with such technique: a solid device (so-called the “phase shifter”) and air (or vacuum). Displacing the solid dielectric material over a propagation line so replacing the air dielectric—creates a phase variation.
The antenna phase shifted feeding network type used today may comprise several dielectric parts, called phase shifters, these parts may sliding under a stripline, or over a microstrip line, as described within the patent application US2004/0080380 and the patent U.S. Pat. No. 6,816,668.
Considering that with such implementation, each radiating element of the panel antenna is potentially unitary phase shifted, the resulting performances of such antenna is very good in terms of performances and stability considering the radiating Electrical cut plane.
The phase shifter of the state of the art comprises the fowling drawbacks:
The proposed electro-mechanical phase shifter reduces the three above mentioned drawbacks and able to deeply reduce the general radio frequency and mechanical constraints related to present Phase Shifter devices, and particularly regarding high frequency bands such as 3.5 GHz and over.
Various embodiments propose phase-shifters that can solve the previously described problems. More specifically, some embodiments provide a phase-shifter.
This summary is provided to introduce concepts related to examples of phase-shifter.
In one implementation, an apparatus forming a phase-shifter is described. The apparatus comprises a strip line and a moving dielectric part. The moving dielectric part surrounds the strip line and is adapted to move only along a longitudinal axis of the strip line. Within this apparatus the size of the area of the strip line surrounded by the moving dielectric part is modified when the moving dielectric part moves along the longitudinal axis.
In one implementation, an antenna is described. The antenna comprises an apparatus forming a phase shifter and the apparatus is placed in a housing of which one of the faces is formed by a chassis of the antenna.
The detailed description is given with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system and/or methods in accordance with embodiments of the present subject matter are now described, by way of example only, and with reference to the accompanying figures, in which:
The
In the present document, the word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment or implementation of the present subject matter described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.
The
In order to have the size of the area of the strip line 101, surrounded by the moving dielectric part 102, modified, when the moving dielectric part 102 moves along a longitudinal axis 103, the strip line 101 can have an L (see enlarged view of the
This embodiment allows a “perfect” mechanical position of phase sifter versus the propagation line. So using this embodiment allows the phase-shifter to work at high frequency bands such as 3.5 GHz and over.
In an embodiment the apparatus also comprises guiding means. These guiding means are configured to guide the movement of the moving dielectric part 102 along the longitudinal axis 103 of the strip line 101.
The
In an embodiment the key 201 is fixed to the strip line 101 or the key 201 and the strip line 101 are both fixed to a ground plate.
In an embodiment the key 201 is a clip made for example of plastic dielectric.
In an embodiment the key is inserted, should have a length at least equal to the width of the strip line, and made from the same dielectric material than the phase shifter device. This avoids any modification of the strip line area where the key is inserted. In this embodiment a slot (or keyway) is placed all along the phase shifter at the corresponding position of the clip, in order to be able to slide it along the longitudinal axe. Within this embodiment, there is no modification of the general radio frequency construction and so the phase shifter behavior isn't modified compared to phase-shifter of the state of the art.
The
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In an embodiment the moving dielectric part 102 are constituted of two identical parts the first part placed over the strip line and the second part placed under the strip line.
In another embodiment the stripe line 101 is made by etching a metal layer of a printed circuit board.
An embodiment of the present subject matter is an antenna that comprises the apparatus of any of the preceding embodiments. The phase-shifter is placed in a housing of which one of the faces is formed by a chassis of the antenna.
In other words the different embodiments of the phase shifter permit to guaranty the “perfect” mechanical position of the moving dielectric part versus the propagation line. Indeed the extra parts (for example the key and keyway) inserted in the different elements of the phase-shifter, and are cause of increasing the mechanical tolerances between the dielectric phase shifters and the propagation line.
In an embodiment and on order to avoid this, and be sure that the phase shifter mechanical positioning is directly referenced to the propagation line, a small part, called “guide” or key. This key or “guide can for example be inserted directly onto the line.
The
One other object of the present subject matter is an antenna comprising one of the phase-shifter previously described. This phase-shifter is placed in a housing of which one of the faces is formed by a chassis of the antenna.
Number | Date | Country | Kind |
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16305649.2 | Jun 2016 | EP | regional |
Filing Document | Filing Date | Country | Kind |
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PCT/IB2017/052852 | 5/15/2017 | WO | 00 |