JPS6224965Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a periodic duplexer used in the millimeter wave band, in which two orthogonal polarization components have different phase constants in the propagation axis direction. This invention relates to a periodic duplexer that excites linearly polarized waves tilted approximately 45 degrees to the direction of the waveguide, and in which a dielectric material is loaded in the waveguide to equalize the spacing of the demultiplexed frequencies.

Conventionally, a periodic duplexer uses two waveguides (main waveguide, sub waveguide) of different lengths, as shown in Figure 1, and divides the input power into two equal output powers. A configuration consisting of two 3dB couplers was used. In FIG. 1, 1 is an output port, 2 and 2' are 3 dB couplers, 3 and 3' are waveguides, and 4 and 4' are output ports.

Next, the principle of operation will be explained. A radio wave with a frequency component of ₁ + ₂ +... + _2o that enters from input port 1 is divided into half energies by a 3 dB coupler 2, one half of which is divided into two halves of energy, one half of which is the main wave tube 3 of length, and the other of which is of length ' They pass through the sub-waveguide 3' and are recombined at the 3 dB coupler 2'. At this time, by appropriately selecting the difference between the lengths of the waveguides 3 and 3', ₁ , ₃ , ..., _2o-1 are in phase at the output port 4,
₂ , ₄ ,..., _2o are in reverse phase, and ₁ + ₃ +...+ _2o-1 is taken out from the output port 4.

On the other hand, the opposite effect occurs at output port 4',
₂ + ₄ +...+ _2o is taken out. However, a periodic duplexer with this configuration requires two main and sub waveguides and a 3dB coupler to connect them, making the configuration complex and difficult to manufacture and adjust. Since the degree of coupling of the 3dB coupler cannot be made constant, there is a limit to the frequency band that can be used.Furthermore, the propagation constant of the waveguide changes with frequency, so the intervals between frequencies that are in-phase or out-of-phase at each output port are different. There were drawbacks such as the frequency interval to be demultiplexed was not constant.

Among these drawbacks, the two points that are difficult to manufacture and adjust due to its complicated configuration, and the limitation of the usable frequency band, have been solved. A configuration has been proposed that eliminates the need for a container. That is, a waveguide in which two orthogonal polarized components have different phase constants in the propagation axis direction is excited with a linearly polarized wave that is tilted approximately 45 degrees to the direction of the two polarized components.

Figure 2 shows an example of this configuration realized with a rectangular waveguide, where 1 is an input port, 3'' is a rectangular waveguide,
4 and 4' are output ports, 5 and 5' are circular rectangular conversion waveguides, 6 is a circular tapered waveguide, and 7 is a polarization splitter.

The rectangular waveguide 3″ separates two polarized waves with different propagation constants into a polarized wave component parallel to the x-axis and a polarized wave component parallel to the y-axis, so the direction of the linearly polarized wave incident from the input port 1 is The polarization splitter 7 is installed at an angle of approximately 45 degrees to the direction of the polarization component of one output port 4', in order to separate the incident linearly polarized component and the polarized component orthogonal thereto. It is installed so that the direction of the incident linearly polarized wave coincides with the direction of the incident linearly polarized wave, and the direction of the polarized wave component of the other output port 4 is orthogonal to the direction of the incident linearly polarized wave. The arrow inside represents the direction of polarization and its strength.

Next, the operating principle will be explained. In FIG. 2, the linearly polarized wave incident from the input port 1 is converted into a rectangular waveguide by a circular rectangular conversion waveguide 5. At this time, the direction of linear polarization of the incident wave is approximately 45 degrees with respect to the orthogonal x-axis and y-axis on the rectangular waveguide side, so it functions similarly to a 3dB coupler, and the incident wave is directed along the x-axis. The parallel polarized wave component (hereinafter referred to as x-polarized wave component) and the polarized wave component parallel to the y-axis (hereinafter referred to as y-polarized wave component) are separated into two parts and guided to the rectangular waveguide 3''. Since the wave tube 3'' has different cross-sectional dimensions on the x-axis and y-axis, the propagation constants are different between the x-polarized wave component and the y-polarized wave component. For this reason, there is a difference in phase between the x-polarized wave component and the y-polarized wave component when the wave passes through the rectangular waveguide 3'' and enters the circular-rectangular conversion waveguide 5', and this is converted into the polarization of the incident wave. Considering the parallel components and the polarization components orthogonal to these, in the polarization components parallel to the incident wave, ₂ , ₄ ,..., _2o are periodically in phase, and ₁ , ₃ ,..., _2o-1 are in the opposite phase. In addition, the polarized wave components perpendicular to this are in the opposite state. Therefore, these two polarized wave components are connected to a polarization splitter using a circular tapered waveguide 6, and the polarized wave components are polarized. The demultiplexer 7 separates these two components, and the output port 4,
4', output port 4 outputs ₁ +
₃ +...+ _2o-1 , ₂ + from output port 4'
The frequency of ₄ +...+ _2o is extracted and operates as a periodic duplexer.

FIG. 3 shows the frequency characteristics of a periodic duplexer having this configuration. As is clear from FIG. 3, the center frequency spacing of the channels is narrower in lower frequency bands and wider in higher frequency bands. It can also be seen that the rise in frequency characteristics is sinusoidal and not sharp.
The reason why the separated frequency interval is not constant is that the propagation constants of the x-polarized wave component and the y-polarized wave component change with frequency, similar to the configuration shown in FIG.

In order to eliminate this drawback, the present invention loads a dielectric material into the waveguide 3'' shown in Fig. 2 to equalize the frequency intervals for demultiplexing.The present invention will be explained in detail with reference to the drawings below. explain.

FIG. 4 shows an embodiment of the present invention, in which a rectangular waveguide 3'' shown in FIG. The waveguide 3'' is loaded with a dielectric material having a certain thickness in the length direction of the waveguide 3''. The feature of this embodiment is that by appropriately setting the dielectric constant and dimensions of the dielectric material, the X polarization component and the Y polarization component can be
It is possible to make the slope of the phase difference of polarization components with respect to frequency almost constant over a high frequency band.

The amplitude of the waveguide 3″ is a, the height is b, and the length is _0.
The thickness of the dielectric is t, the relative permittivity is ε _r , and X, Y
Letting the propagation constants of each polarization component be γ _e and γ _h , they can be obtained from the following equation using the transverse resonance method.

Here, k ₀ = 2π/λ, λ = c/, c: speed of light, : frequency, and h is the lateral propagation constant in the waveguide. This is a variable that is only used.

Next, the phase difference Δφ() between both polarized waves becomes Δφ()= ₀ (γ _h −γ _e ).

As an example, FIG. 5 shows the characteristics of Δφ( ) and the corresponding output power characteristics of port 4' when a=12, b=8, ε _r =2 and t=0 to 6.

Here, the case of t=6 corresponds to the present embodiment, and the case of t=0 corresponds to the configuration shown in FIG. 2. As is clear from this, in the conventional configuration, the phase difference characteristic is not proportional to the frequency, so at the point where it enters the circular-to-rectangular conversion waveguide 5', the polarization component that is the same as the linearly polarized wave of the incident wave is , ₂ , ₄ ... _2o are in phase at different frequency intervals, and ₁ , ₃ ... _2o-1 are out of phase at different frequency intervals. Furthermore, the polarized wave component orthogonal to the incident wave is in the opposite state. That is, in the demultiplexed outputs taken out from the output ports 4 and 4', the demultiplexed frequency intervals are unequal, as shown by the output power characteristics of the port 4' when t=0 in FIG. On the other hand, in the case of this embodiment, since the phase characteristic is proportional to the frequency, at the point where the wave enters the circular-to-rectangular conversion waveguide 5', the polarization component is the same as the linearly polarized wave of the incident wave. ,
₂ , ₄ ,..., _2o are in phase at the same frequency interval, and ₁ , ₃ ,..., _2o-1 are at opposite phase at the same frequency interval. In addition, the polarization component orthogonal to the incident polarization is in the opposite state. In other words, in the divided outputs taken out from the output ports 4 and 4', the frequency interval is kept almost constant over a wide frequency band, as shown in the output power characteristics of port 4' when t=6 in Figure 5. It becomes possible to do so.

As explained above, the periodic duplexer using orthogonal polarization of the present invention consists of a waveguide and a polarization duplexer whose main components are two orthogonal polarization components with different phase constants in the propagation axis direction. In the periodic duplexer, a dielectric material is added within the waveguide having different phase constants,
By making the primary slope of the propagation constant constant with respect to frequency changes using two orthogonal polarization components, it has an outstanding effect as a periodic duplexer in that the frequency interval output to the output port can be made constant.

[Brief explanation of the drawing]

Figure 1 is a diagram explaining the principle of a conventional periodic duplexer, Figure 2
The figure is a perspective view showing the configuration of a conventional periodic duplexer.
The figure is a branching characteristic diagram of a conventional periodic duplexer, Figure 4 is a perspective view showing the configuration of an embodiment of a periodic duplexer using orthogonal polarization according to the present invention, and Figure 5 is a periodic duplexer according to the present invention. FIG. 4 is a diagram showing the phase difference between the X polarization and Y polarization of the duplexer and the output power characteristics of the port 4' corresponding to the phase difference. 1...Input port, 2,2'...3dB coupler,
3, 3', 3''... Rectangular waveguide, 4, 4'... Output port, 5, 5'... Circular-square conversion waveguide, 6...
...Circular taper waveguide, 7...Polarization splitter, 8...Dielectric material.

Claims (1)

[Scope of utility model registration request] A rectangular waveguide in which two orthogonal polarized components have different phase constants in the propagation axis direction, a circular-to-rectangular conversion waveguide connected to the input side and output side of this waveguide, and this conversion waveguide. a circular tapered waveguide connected to the output side of the waveguide, and a polarization splitter connected to the output side of the circular taper waveguide, and the rectangular waveguide The polarization splitter is installed at an angle of approximately 45 degrees, and the polarization splitter matches the direction of the polarized wave component of one output port with the direction of the incident linearly polarized wave,
and installed so that the direction of the polarized wave component of the other output port is orthogonal to the direction of the incident linearly polarized wave, and the waveguide is installed in the rectangular waveguide at approximately the center in the lateral direction of the waveguide. A dielectric of the same height as the waveguide is loaded in the length direction of the waveguide, and ) - A periodic duplexer using orthogonal polarization.