Patent Application
20130277717
This application claims the benefit of Korean Patent Application No. 10-2012-0041986, filed on Apr. 23, 2012, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a frequency control device having an improved isolation feature, and more particularly, to a technology that may reduce manufacturing costs by increasing an isolation feature and reducing an area of a switch device, when at least two ground holes are placed in both ends of a source or a drain of the switch device.
2. Description of the Related Art
As shown in
In the frequency control device 104, a depletion region of the frequency control device 104 may be controlled to be turned on or off by a control device control voltage applied to a gate electrode 103 of the frequency control device 104. Accordingly, a short from a drain electrode of the frequency control device 104 to a source electrode of the frequency control device 104, and a short from the source electrode to the drain electro may be determined.
For example, when the frequency control device 104 is in an off state, a frequency may be output from the input terminal 101 to the output terminal 102, as indicated by a solid-line arrow 106, or may be output from the output terminal 102 to the input terminal 101.
Additionally, when the frequency control device 104 is in an on state, a frequency may be output, as indicated by a dotted-line arrow 107. This is because all frequency components are output to a ground 105 and a frequency component is not output to the output terminal 102, since an impedance of the ground 105 is greater than an impedance of the output terminal 102.
When the frequency control device 104 is in the on state, the equivalent circuit may be represented by Ron 108 and Ls 109, as shown in
When the frequency control device 104 is in the on state, the equivalent circuit may be regarded as transmission lines 110 and 111 of
As a result of interpreting the graph 400, an isolation feature of at least about 10 decibel (dB) is shown up to a frequency of 25 GHz. Disadvantages of an increase in an area by setting an electrical length of the transmission line 111 to 4/λ to obtain the isolation feature of at least about 10 dB at a high frequency of at least 25 GHz, have been indicated.
According to an aspect of the present invention, there is provided a switch device using a single-pole, single-throw (SPST) field-effect transistor (FET), including: a transmission line including an input terminal and an output terminal; and a frequency control device to switch a frequency input to the input terminal so that the frequency is selectively transferred to the output terminal, wherein the transmission line is formed in the form of an air bridge, in an upper portion of the frequency control device.
The frequency control device may include a gate electrode to receive an input of a control device control voltage, and to control a depletion region to be turned on or off, and a source electrode and a drain electrode determined to be grounded or shorted based on a control of the gate electrode.
The transmission line may be connected perpendicularly to the source electrode or the drain electrode, and one of the gate electrode, the drain electrode and the source electrode may be consecutively connected.
The transmission line may be connected to at least one ground.
The transmission line may be connected to a plurality of grounds, and the plurality of grounds connected to the transmission line may be symmetrically connected to each other in a vertical position or a horizontal position of the transmission line.
The source electrode and the drain electrode may be connected to at least one ground.
According to embodiments of the present invention, at least two ground holes may be placed in both ends of a source or a drain of a switch device, and accordingly it is possible to reduce manufacturing costs by increasing an isolation feature and reducing an area of the switch device.
These and/or other aspects, features, and advantages of the invention will become apparent and more readily appreciated from the following description of exemplary embodiments, taken in conjunction with the accompanying drawings of which:
Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. Exemplary embodiments are described below to explain the present invention by referring to the figures.
The switch device of
The frequency control device may include a gate electrode, a source electrode, and a drain electrode. The gate electrode may receive an input of a control device control voltage, and may control a depletion region to be turned on or off. The source electrode and the drain electrode may be determined to be connected to a ground 504 or shorted, based on a control of the gate electrode.
The transmission lines 501, 502 and 506 may be connected perpendicularly to the source electrode or the drain electrode. One of the gate electrode, the source electrode, and the drain electrode may be consecutively connected.
First, the transmission lines 501 may be connected perpendicularly to a source electrode or a drain electrode of a field-effect transistor (FET), and a gate electrode, the source electrode and the drain electrode of the FET may be consecutively connected.
To connect the transmission lines 501 to each other, the transmission line 502 may be formed in the form of the air bridge, in the upper portion of the frequency control device. In this instance, the transmission line 502 may not need to be connected to the transmission line 505, or a device electrode connected to the transmission line 505. The transmission line 505 may be connected to the ground 504.
When the frequency control device is in an on state, an equivalent circuit may be represented by Ron and Ls. In the equivalent circuit, the Ron may indicate a unique physical property of a semiconductor substrate, since the Ron has relevance to formation of a channel of an FET.
Accordingly, when Ls is reduced, an isolation feature and a high frequency feature may be improved.
Additionally, since Ls is determined based on a physical structure of the ground 504. To reduce Ls, two Ls 206 may be inserted as shown in
As shown in
The equivalent circuit of
The frequency control device 901 of
Although a few exemplary embodiments of the present invention have been shown and described, the present invention is not limited to the described exemplary embodiments. Instead, it would be appreciated by those skilled in the art that changes may be made to these exemplary embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2012-0041986 | Apr 2012 | KR | national |
