JPH05136603A - Waveguide type diode limiter - Google Patents

Abstract

PURPOSE:To make a miniaturized and low-priced device, to make unnecessary a PIN diode attenuator and to improve the receiving sensitivity for it by providing a waveguide type diode limiter using a PIN diode with an attenuation function besides a limiter function and incorporating that into a large electric power pulse radar system. CONSTITUTION:In a ridge waveguide 11 where a ridge part 12 is formed at the center of a tube wall, at least two PIN diodes 26 and 33 are arranged in the forming direction of the ridge part 12 with the prescribed interval. At least one electrode of the PIN diodes 26 and 33 is not directly coupled with the wall surface of the waveguide 11, is drawn to the outside of the waveguide 11, and by using this, the bias current can be made to flow at the PIN diode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveguide type diode limiter having an attenuator function, which is used in, for example, a high power pulse radar device.

[0002]

2. Description of the Related Art Here, one example of a device in which a waveguide type diode limiter is used is a large power (25k) for a large ship.
W) An explanation will be given using a pulse radar device.

FIG. 4 is a circuit configuration diagram of a high-power pulse radar device, and 1 is a magnetron for generating a transmission signal.
This transmission signal is radiated from the antenna 3 via the circulator 2. The reflected wave from the target is received by the antenna 3, passes through the circulator 2, and passes through the diode limiter 4
Added to. The reflected wave that has passed through the diode limiter 4 passes through the next PIN diode attenuator 5 and is introduced into the reception module 6. The outline of the configuration of the high-power pulse radar device is as described above. Here, in the diode limiter 4, among the transmission signals sent from the magnetron 1, an excessive high frequency signal leaking from the circulator 2 is
The reception module 6 is protected so as not to join the reception module 6.

The PIN diode attenuator 5 prevents the reflected wave of high power reflected by a target at a short distance from being added to the receiving module 6 and saturating the receiving module 6.

As described above, in the high power pulse radar device, the diode limiter is used to protect the reception module from the sneak of the transmission signal from the circulator.

A PIN diode attenuator is also used to prevent saturation of the receiver module 6 due to high power reflected waves from a short range target.

[0007]

Conventionally, as described above, the diode limiter for protecting the receiving module from the excessive high frequency signal and the saturation of the receiving module 6 due to the high power reflected wave from the short distance target are prevented. The PIN diode attenuator is composed of separate parts. Therefore, the size of the high-power pulse radar device using these is large and the price is also high.

Further, since the high-power radar device identifies a long-distance target object, it is important that the reception sensitivity is good. However, the residual loss of the PIN diode attenuator is about 1 dB, which also causes deterioration of reception sensitivity.

[0009]

A diode limiter is constructed by disposing a plurality of PIN diodes in a ridge waveguide having protrusions formed on a tube wall. A bias current can be passed through the PIN diode.

[0010]

According to the above construction, since one diode limiter has a limiter function and an attenuation function, when this is incorporated in, for example, a high power pulse radar device, the device can be downsized and the price can be reduced. it can. Also, PIN
Since a diode attenuator is not required separately, the receiving sensitivity can be improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

1A and 1B show a waveguide type diode limiter of the present invention. FIG. 1A is a top view, FIG. 1B is a bottom view, and FIG. 1C is a sectional view taken along line AA of FIG. (e) is a partially enlarged view in the AA cross-sectional view, (f) is a BB cross-sectional view of the bottom view (c), with internal parts removed.

An embodiment of the waveguide type diode limiter of the present invention will now be described with particular reference to FIGS. 1 (b) and (e).

Reference numeral 11 denotes a ridge portion 12 at the center of the waveguide wall.
Is a ridge waveguide formed with. Further, holes 13 and 14 are formed in the tube wall where the ridge portion 12 is formed with a certain distance in the extension direction of the ridge portion. In this case, the ridge portion 1
Part of 2 is also removed according to the size of holes 13 and 14.

Further, the screw holes 15 and 16 are provided in the holes 13 and 14, respectively.
To form. These screw holes 15 and 16 respectively have
The ring-shaped screw parts 17 and 18 are screwed in, and their positions can be adjusted. The center frequency of operation can be adjusted by adjusting the positions of the screw parts 17 and 18.

Further, screw rods 19 and 20 are screwed into the centers of the screw parts 17 and 18, respectively, and outer peripheral walls of the holes 13 and 14 are coaxial outer conductors, and the screw rods 19 and 20 are coaxial inner conductors. , A short circuit is formed by the screw parts 17 and 18.

Further, as shown in detail in the enlarged view of FIG. 2 (e), the waveguide wall 2 on the side where the coaxial circuit is not formed is shown.
1 has a hole 22 formed therein, and a choke component 23 is incorporated using the hole 22.

The choke component 23 is attached to the hole 22 provided in the waveguide wall 21 on the side without the ridge portion so as to sandwich the insulating sheet 24a. The insulating tube 24
The insulating sheet 24c and the insulating sheet 24c are for maintaining the insulation between the choke component and the waveguide wall, and are dielectrics.

The PIN diode 26 is mounted in the diode mounting hole 25 provided in the choke component 23, and the tip of the screw component 19 is crimped and fixed.

The choke part 23 is an insulating tube 24.
b, it is insulated from the tube wall 11 by the insulating sheet 24c. Further, a lead terminal 31 for applying a bias voltage to the diode 26 is connected to the lug component 27 connected to the screw 28. The detection diode 29 and the resistor 30 are connected in parallel to the lead terminal 31. The other ends of the detection diode 29 and the resistor 30 are DC-connected to the tube wall of the waveguide by a lug part and a screw for attaching the lug part.

On the other hand, as shown in FIG. 6F, there is a diode mounting hole 32 on the surface facing the hole 14, and another PIN diode 33 is crimped and fixed by the screw rod 20. In the waveguide type diode limiter having the above configuration, when a high-frequency signal of high power is input from the opening of the waveguide, part of the high-frequency signal leaks to the lug component 27 through the choke component 23. The leaked high frequency signal is detected by the detection diode 29. The detected current flows in the forward direction to the diode 26 through the tube wall of the waveguide. As a result, the diode 26 becomes conductive and functions as a limiter. Since both ends of the other limiter diode 33 are directly coupled to the tube wall of the waveguide, a forward current flows by a high-power high-frequency signal and functions as a limiter. When used in a high-power pulse radar device, it can function as an attenuator if a forward current is passed from the lead terminal 31 to the limiter diode 26 when receiving a reflected wave.

Here, the characteristics when the waveguide type diode limiter of the present invention is made to function as a limiter without applying a bias voltage to the lead terminal 31 will be described with reference to FIG.

In the graph of FIG. 2, (a) shows a case where the power of the high frequency signal applied to the waveguide type diode limiter is low, and (b) shows a case where the power of the high frequency signal applied to the waveguide type diode limiter is high. In each case, the vertical axis represents loss (unit: dB) and the horizontal axis represents frequency.

As can be seen from FIG. 3A, when the power of the high frequency signal is low, the loss of the waveguide type diode limiter is
It becomes the minimum at the fundamental frequency, and increases to about 50 dB in the frequency band higher than that.

Further, as can be seen from FIG. 6B, when the power of the high frequency signal is high, the loss of the waveguide type diode limiter increases up to the frequency band including the fundamental wave frequency and functions as a limiter. is doing.

FIG. 3 shows the characteristics when the waveguide type diode limiter of the present invention is made to function as an attenuator, in which the vertical axis represents loss (unit: dB) and the horizontal axis represents bias current (unit: μA). ) Is taken.

Curve A shows the case where the high frequency signal ingress side, that is, the PIN diode of the first stage is used as the attenuator, and curve B shows the case where the PIN diode of the next stage is used as the attenuator. In general, since the PIN diode of the first stage has a thicker I layer, the characteristics differ when the PIN diode of the first stage is used as an attenuator and when the PIN diode of the next stage is used as the attenuator.

In the above-mentioned embodiment, the diode is attached by opening the diode attachment hole in the flat waveguide wall in which the ridge portion is not formed. Therefore, it is easy to attach a choke component that applies a bias from the outside.

In the above embodiment, when it functions as an attenuator, the detection current is passed through only one diode. However, the other PIN diode can also have a function as an attenuator by not connecting both ends thereof directly to the waveguide wall but by making a detection current flow.

The waveguide type diode limiter of the present invention can be constructed by a double ridge waveguide having ridge portions formed on both upper and lower tube walls. Further, the number of PIN diodes forming the waveguide type diode limiter is not limited to two and may be three or more.

[0031]

According to the present invention, since one waveguide type diode limiter has a limiter function and an attenuation function,
When this is incorporated into, for example, a high-power pulse radar device, the device can be downsized and the price can be reduced. Further, since the PIN diode attenuator is not required separately, the receiving sensitivity can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing characteristics of the present invention.

FIG. 3 is a diagram showing characteristics of the present invention.

FIG. 4 is a circuit configuration diagram of a high power pulse radar device in which the present invention is used.

[Explanation of symbols]

 11 ... Ridge waveguide 12 ... Ridge part 13, 14 ... Hole 15, 16 ... Screw hole part 17, 18 ... Screw component 19, 20 ... Screw rod 21 ... Waveguide wall 22 ... Hole 23 ... Choke component 24a ... Insulation Sheet 24b ... Insulating tube 24c ... Insulating sheet 25 ... Diode mounting hole 26 ... PIN diode 27 ... Lug component 28 ... Screw 29 ... Detection diode 30 ... Resistor 31 ... Lead terminal 32 ... Diode mounting hole 33 ... PIN diode

Claims (5)

[Claims] 1. A ridge waveguide in which a ridge portion is formed in the center of the lower surface of a tube wall, and at least a ridge waveguide having a predetermined distance in the direction of formation of the ridge portion and arranged to face the ridge portion. Two PIN diodes and one end of the P
DC connection with at least one IN diode,
A waveguide-type diode limiter, the other end of which is drawn out of the waveguide and has a lead terminal for supplying a bias current to the PIN diode. 2. The waveguide type diode limiter according to claim 1, wherein a part of the PIN diode is located in a concave space formed in the waveguide wall on the side where the ridge portion is not present. 3. The waveguide type diode limiter according to claim 1, wherein both ends of one PIN diode are galvanically coupled to the waveguide wall. 4. A waveguide diode according to claim 1, wherein a detection diode is connected to the lead terminal, and an output current detected by the detection diode flows to a PIN diode connected to the lead terminal. limiter. 5. The waveguide type diode limiter according to claim 1, wherein the ridge waveguide is a double ridge waveguide in which ridge portions are formed on both upper and lower surfaces.