Patent Grant
7629861
1. Field of the Invention
The invention relates to temperature compensation attenuators for compensating temperature characteristics of high frequency or microwave devices and systems used in electronics and communication. The attenuators can be applied in various circuits and systems utilizing high frequency waves or microwaves, and more particularly, are suitable for use in mobile communication systems, satellite communication systems, satellite navigational systems, and radar systems which require strict temperature characteristics.
2. Description of the Related Art
Current techniques for reducing the temperature drift of high frequency or microwave active devices are quite complex, utilize many applied components, and exhibit lengthy R&D periods, high cost, and high rate of failure. For example, the gain of high frequency or microwave power amplifiers, and thus their power output, varies with external temperature, seriously deteriorating the characteristics and stability of the amplifiers and even of the entire systems.
To reduce the variance in the gain and the power of high frequency or microwave power amplifiers resulting from the variance in environmental temperature, many active devices, such as temperature detectors, power couplers, wave detectors, programmable signal processors, storage, and preamplifiers with automatic gain control (AGC) and automatic power control (APC) capabilities are included in the amplifiers themselves, their power sources and their control systems. Moreover, it is a prominent problem to increase rated power of the attenuator while maintaining the same size of substrates and materials.
While resolving the temperature drift characteristics, several features of the devices must be satisfied:
One objective of the invention is to provide a temperature compensation attenuator to realize the compensation of the temperature characteristic of high frequency or microwave active devices and systems in electronics and communications.
In one embodiment of the invention described herein, provided is a temperature compensation attenuator comprising: a base; a film thermistor having two edges; a film resistor having a first edge, a second edge; and a third edge; an input terminal; an output terminal and a ground terminal; wherein the film thermistor and the film resistor are disposed on the base; one edge of the film thermistor is contacted to the input terminal; the other edge of the film thermistor is contacted to the output terminal; the first edge of the film resistor is contacted to the input terminal; the second edge of the film resistor is contacted to the output terminal; and the third edge of the film resistor is contacted to the ground terminal.
In a class of this embodiment, the film thermistor has a negative temperature coefficient or a positive temperature coefficient.
In another class of this embodiment, the film thermistor is a thick film thermistor or a thin film thermistor.
In another class of this embodiment, the film resistor is a thick film resistor or a thin film resistor.
In another class of this embodiment, the film thermistor is polygon-shaped or arc-shaped.
In another class of this embodiment, the film resistor is polygon-shaped or arc-shaped.
In a second embodiment of the invention described herein, provided is a temperature compensation attenuator comprising: a base; a film resistor having two edges; a film thermistor having a first edge, a second edge, and a third edge; an input terminal; an output terminal; and a ground terminal; wherein the film resistor and the film thermistor are disposed on the base; one edge of the film resistor is contacted to the input terminal; the other edge of the film resistor is contacted to the output terminal; the first edge of the film thermistor is contacted to the input terminal; the second edge of the film thermistor is contacted to the output terminal; and the third edge of the film thermistor is contacted to the ground terminal.
In a class of this embodiment, the film thermistor has a negative temperature coefficient or a positive temperature coefficient.
In another class of this embodiment, the film resistor is a thick film resistor or a thin film resistor.
In another class of this embodiment, the film thermistor is a thick film thermistor or a thin film thermistor.
In another class of this embodiment, the film thermistor is polygon-shaped or arc-shaped.
In another class of this embodiment, the film resistor is polygon-shaped or arc-shaped.
In a third embodiment of the invention described herein, provided is a temperature compensation attenuator comprising: a base; a first film thermistor having two edges; a second film thermistor having a first edge, a second edge; and a third edge; an input terminal; an output terminal; and a ground terminal; wherein the first film thermistor and the second film thermistor are disposed on the base; one edge of the first film thermistor is contacted to the input terminal; the other edge of the first film thermistor is contacted to the output terminal; the first edge of the second film thermistor is contacted to the input terminal; the second edge of the second film thermistor is contacted to the output terminal; the third edge of the second film thermistor is contacted to the ground terminal; and the first film thermistor has a temperature characteristic that is opposite to that of the second film thermistor.
In a class of this embodiment, the first film thermistor has a negative temperature coefficient.
In another class of this embodiment, the second film thermistor has a positive temperature coefficient.
In another class of this embodiment, the first film thermistor has a positive temperature coefficient.
In another class of this embodiment, the second film thermistor has a negative temperature coefficient.
In another class of this embodiment, the first film thermistor is a thick film thermistor or a thin film thermistor.
In another class of this embodiment, the second film thermistor is a thick film resistor or a thin film resistor.
In another class of this embodiment, the first film thermistor and the second film thermistor are polygon-shaped or arc-shaped.
As a result, by utilizing the film thermistor of the invention, a wideband temperature compensation attenuator with a distributed parameter circuit structure is constructed wherein the amount of attenuation varies with temperature. By connecting the temperature compensation attenuator of the invention to a high frequency or microwave active circuit, the variance of the gain of the high frequency or microwave active device or the drift of the frequency characteristic of the active device resulting from temperature variance can be compensated. Even under large environmental temperature variance, the attenuator of the invention can still ensure stability of the gain of the high frequency or microwave active device and compensate for the drift of the frequency characteristic of the active device.
Accordingly, the invention provides embodiments with the following advantages:
Detailed description will be given below with reference to accompanying drawings.
As shown in
Taking a temperature compensation attenuator having an attenuation of 3 dB at 25° C. as an example of this embodiment, it is required that a frequency thereof is DC-6 GHz, the temperature is between −40° C. and +105° C., and the attenuation is between 5 dB and 1.8 dB. In this embodiment, the film thermistor 1 has a NTC and a resistance of 17 Ohm at 25° C. The resistance between the first edge 2-1 and the second edge 2-2 of the film resistor and that between the second edge 2-2 and the third edge 2-3 are equal to 152 Ohm. The following data are obtained: as temperature changes from 25° C. to −40° C., the attenuation changes from 3 dB to 5.1 dB; as the temperature changes from 25° C. to +105° C., the attenuation changes from 3 dB to 1.8 dB, and the standing wave ratio (SWR) is less than 1.3 at the frequency of 1 GHz.
Referring to
Referring to
Referring to
Referring to
While the first film thermistor 111 has a NTC, the second film thermistor 222 has a PTC, and the attenuator is a temperature compensation attenuator. While the first film thermistor 111 has a PTC, the second film thermistor has a NTC, and the attenuator is an RF switch.
The first film thermistor 111 is a thick film thermistor or a thin film thermistor, and the second film thermistor 222 is a thick film resistor or a thin film resistor.
The first film thermistor 111 and the second film thermistor 222 are polygon-shaped, arc-shaped. circle-shaped, or oval-shaped.
Compared with the first embodiment and the second embodiment, the attenuator of this embodiment has the best RF characteristics, and variation in the attenuation of the attenuator caused by temperature change is the largest.
This invention is not to be limited to the specific embodiments disclosed herein and modifications for various applications and other embodiments are intended to be included within the scope of the appended claims. While this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, specification, and following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004 1 0027307 | May 2004 | CN | national |
| 2008 1 0190568 | Dec 2008 | CN | national |
This application is a continuation in part of U.S. Ser. No. 12/106,408 filed on Apr. 21, 2008, now pending, which is a continuation in part of U.S. Ser. No. 10/597,985 filed on Apr. 28, 2005, now U.S. Pat. No. 7,362,196, granted Apr. 22, 2008, which is a National Stage Application of International Patent Application No. PCT/CN2005/000586, which is based on Chinese Patent Application No. 200410027307.7, filed May 18, 2004. This application further claims priority pursuant to 35 U.S.C. § 119 and the Paris Convention Treaty to Chinese Patent Application No. 200810190568.9 filed Dec. 7, 2008. The contents of all of these specifications are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 20090160601 A1 | Jun 2009 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12106408 | Apr 2008 | US |
| Child | 12394267 | US | |
| Parent | 10597985 | US | |
| Child | 12106408 | US |
