Patent Application
20220209383
Some references, which may include patents, patent applications and various publications, may be cited and discussed in the description of this disclosure. The citation and/or discussion of such references is provided merely to clarify the description of the present disclosure and is not an admission that any such reference is “prior art” to the disclosure described herein. All references cited and discussed in this specification are incorporated herein by reference in their entireties and to the same extent as if each reference was individually incorporated by reference.
For a millimeter wave of a higher frequency band (ranging from 26.5 GHz to 29.5 GHz), a wavelength of the signal is very short when a frequency of the signal is extremely high. When the shortened wavelength is comparable to a length of the transmission line, a reflected signal at the terminal of the transmission line is superimposed on the signal, and a shape of a signal waveform is accordingly changed. If the characteristic impedance of the transmission line is not matched with (or is not equal to) a load impedance of the termination, the reflection occurs at a load terminal.
Since the millimeter wave has an extremely high frequency, the reflection of the signal occurs if the chip resistor is connected to the terminal of a millimeter wave transmission line. Accordingly, the conventional 50 ohm chip resistor is not suitable for being utilized as the termination at the terminal of the millimeter wave transmission line, since an ideal matching effect cannot be achieved.
Therefore, how to overcome the above-mentioned inadequacy through improving the structural design has become one of the important issues to be solved in the field.
In certain embodiments, the printed circuit board transmission line includes a second signal feed part, which is electrically connected to the second terminal.
In certain embodiments, the second terminal is an open circuit termination. In certain embodiments, the second terminal is a ground terminal. In certain embodiments, the transmission line has a spiral structure. In certain embodiments, the transmission line has a characteristic impedance of 50 ohms.
In certain embodiments, the transmission line has a characteristic impedance of 80 ohms.
In certain embodiments, the signal feed part has a characteristic impedance of 50 ohms.
In certain embodiments, the printed circuit board transmission line utilized as the millimeter wave attenuator further includes a quarter-wavelength transformer, which is connected between the signal feed part and the first terminal.
In another aspect, the present disclosure provides a printed circuit board transmission line utilized as a millimeter wave attenuator, which includes a transmission line and a plurality of signal feed parts. The transmission line includes two transmission line main bodies. The two transmission line main bodies are cross-connected. Each of the two transmission line main bodies includes a first terminal and a second terminal. Each of the plurality of signal feed parts is electrically connected to one of the first terminal or one of the second terminals, correspondingly. The transmission line has a predetermined line width and a predetermined line length. One of the plurality of signal feed parts receives an external signal, and the external signal is outputted from another one of the plurality of signal feed parts through the transmission line main bodies. According to a requirement for a signal isolation at two terminals of a line required in a particular application, a signal loss of the transmission line can be between 3 decibels (dB) and 40 decibels (dB) through a cooperation of the predetermined line width and the predetermined line length of the transmission line, so that the transmission line is capable of being utilized as the millimeter wave attenuator. Further, when the transmission line is utilized as a millimeter wave termination, the signal loss of the transmission line can be 20 decibels (dB) by adjusting the predetermined line width and the predetermined line length.
In certain embodiments, a part of each of the two transmission line main bodies near corresponding one of the plurality of signal feed parts has a hairpin structure.
Therefore, in the printed circuit board transmission line utilized as the millimeter wave attenuator provided by the present disclosure, the transmission line can be equivalent to a resistor and achieve a matching effect for functioning as the millimeter wave attenuator by virtue of “the signal loss of the transmission line being between 3 decibels and 40 decibels through the cooperation of the predetermined line width and the predetermined line length” and by a physical characteristic of having a higher loss when the transmission line has a longer path.
These and other aspects of the present disclosure will become apparent from the following description of the embodiment taken in conjunction with the following drawings and their captions, although variations and modifications therein may be affected without departing from the spirit and scope of the novel concepts of the disclosure.
The described embodiments may be better understood by reference to the following description and the accompanying drawings, in which:
and
The terms used herein generally have their ordinary meanings in the art. In the case of conflict, the present document, including any definitions given herein, will prevail. The same thing can be expressed in more than one way. Alternative language and synonyms can be used for any term(s) discussed herein, and no special significance is to be placed upon whether a term is elaborated or discussed herein. A recital of one or more synonyms does not exclude the use of other synonyms. The use of examples anywhere in this specification including examples of any terms is illustrative only, and in no way limits the scope and meaning of the present disclosure or of any exemplified term. Likewise, the present disclosure is not limited to various embodiments given herein. Numbering terms such as “first”, “second” or “third” can be used to describe various components, signals or the like, which are for distinguishing one component/signal from another one only, and are not intended to, nor should be construed to impose any substantive limitations on the components, signals or the like.
Referring to
Furthermore, the transmission line 1 as shown in
It is worth mentioning that the printed circuit board transmission line M of the present disclosure refers to a wiring structure of the printed circuit board transmission line, so that the first terminal 11 and the second terminal 12 can be arranged on different layers of a printed circuit board, and do not need to be arranged on the same plane. However, the present disclosure is not limited thereto. In another embodiment, the second terminal 12 of the transmission line 1 does not need to be connected to another signal feed part; instead, an open circuit termination or a ground terminal is formed at the second terminal 12 of the transmission line 1. As shown in
The same effect can be achieved by the second terminal 12 that is the open circuit termination or the ground terminal, since each of an open circuit and a short circuit to ground in a radio frequency signal transmission causes a total reflection. Accordingly, as long as a path length (i.e., the predetermined line length S) of the transmission line 1 is long enough, a return loss of 20 decibels (dB), which is equivalent to a conventional terminal resistor, can also be achieved after the total reflection.
Further, the return loss of 20 decibels (dB) signifies that a reflected power of the signal is 1% of an incident power of the signal. In other words, the reflected power of the signal is extremely small compared to the incident power of the signal, which results in an excellent matching effect. In the present disclosure, the printed circuit board transmission line M replaces a chip resistor to serve as the termination, so that the signal loss of the transmission line 1 equals to the return loss generated when the transmission line 1 is utilized as the termination. That is, in the present disclosure, the return loss of 20 decibels (dB) can be achieved by having the printed circuit board transmission line M replace the chip resistor to serve as the termination.
As mentioned above, the path length (i.e., the predetermined line length S) of the transmission line 1 needs to be long enough, and also needs to meet an area limitation in the printed circuit board. Accordingly, the transmission line 1 is wired in a manner by which a specific shape is formed through winding. For example, as shown in
Referring to
Since the predetermined length width W of the transmission line 1 in the second embodiment is narrower than the predetermined length width W of the transmission line 1 in the first embodiment, the transmission line 1 in the second embodiment and the transmission line 1 in the first embodiment have different characteristic impedances. For example, the transmission line 1 in the first embodiment can have a characteristic impedance of 50 ohms, while the transmission line 1 in the second embodiment can have a characteristic impedance of 80 ohms. It is worth mentioning that the signal feed part 2 and the transmission line 1 do not necessarily have the same characteristic impedance. Accordingly, in the present embodiment, when the transmission line 1 has the characteristic impedance of 80 ohm, the signal feed part 2 can have the characteristic impedance of 50 ohm. Under such circumstance, the printed circuit board transmission line M can further include a quarter-wavelength transformer 4. The quarter-wavelength transformer is an impedance-matching component used to connect to a middle section where an input impedance is not matched with an output impedance. In the present embodiment, the quarter-wavelength transformer 4 is electrically connected between the signal feed part 2 and the first terminal 11 of the transmission line 1. The signal feed part 2 is matched with the transmission line 1 through a connection of the quarter-wavelength transformer 4, so as to reduce a loss of energy reflection during the signal transmission.
Referring to
Main differences between the third embodiment and the first embodiment and the second embodiment include the shape of the transmission line 1 and a quantity of the signal feed parts 2. In the present embodiment, the quantity of the signal feed parts 2 is four. The transmission line 1 has the two transmission line main bodies A, B that are cross-connected. A part of each of the two transmission line main bodies A, B near a corresponding one of the signal feed parts 2 has a hairpin structure. As shown in
Since the transmission line main body A and the transmission line main body B are cross-connected, in the present embodiment, the signal transmission is not limited to the transmission between the first terminal 11 of the transmission line main body A and the second terminal 12 of the transmission line main body A, or between the first terminal 11 of the transmission line main body B and the second terminal 12 of the transmission line main body B. For example, the first terminal 11 of the transmission line main body A can transmit the signal with the first terminal 11 of the transmission line main body B or the second terminal 12 of the transmission line main body B, and the second terminal 12 of the transmission line main body A can also transmit the signal with the first terminal 11 of the transmission line main body B or the second terminal 12 of the transmission line main body B.
In conclusion, one of the beneficial effects of the present disclosure is that, in the printed circuit board transmission line utilized as the millimeter wave attenuator provided by the present disclosure, the transmission line 1 can achieve a matching effect for functioning as the attenuator by virtue of “the signal loss of the transmission line 1 being between 3 decibels and 40 decibels through the cooperation of the predetermined line width and the predetermined line length” and by a physical characteristic of having a higher loss when the transmission line 1 has a longer path.
Further, a degree of the signal loss depends on the length and the characteristic impedance of the transmission line. The characteristic impedance of the transmission line is decided by the transmission line width, a dielectric thickness of a stack of the printed circuit board, a material property of the stack (e.g., a dielectric constant (Dk) and a dielectric loss (Df)), process parameters (such as surface roughness of a copper line layer on the printed circuit board), etc. In other words, adjusting the degree of the signal loss is not easy. Through the cooperation of the predetermined line width W and the predetermined line length S of the transmission line 1 (when the predetermined length S is 500 mm and the predetermined line width W is 45 μm), the printed circuit board transmission line utilized as the millimeter wave attenuator provided by the present disclosure has the signal loss (also called the insertion loss) of 20 decibels (dB).
The foregoing description of the exemplary embodiments of the disclosure has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching.
The embodiments were chosen and described in order to explain the principles of the disclosure and their practical application so as to enable others skilled in the art to utilize the disclosure and various embodiments and with various modifications as are suited to the particular use contemplated.
Alternative embodiments will become apparent to those skilled in the art to which the present disclosure pertains without departing from its spirit and scope.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202011607622.2 | Dec 2020 | CN | national |
