JPH0125364Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a high-frequency signal switching device used in electrical equipment that uses high-frequency signals in the VHF band and UHF band. The purpose of this is to prevent interference with nearby high-frequency equipment.

Generally, when trying to switch a high-frequency signal path with a frequency of several 10 MHz to about 1000 MHz, the higher the frequency, the greater the electrostatic coupling and electromagnetic coupling due to the minute capacitance and inductance between components, and the signal path The isolation between them is significantly reduced.
Conventional high-frequency signal switching devices using multi-circuit switches have complicated configurations, and it is extremely difficult to obtain isolation of 60 dB or more in the UHF band of 500 MHz or higher.

Although the present invention is simple, it is extremely effective, achieving isolation of 70 dB or more in the frequency band below 1000 MHz, and provides an inexpensive high-frequency signal switching device.

Below, an example of the basic configuration of the present invention will be described in the case of a single-pole, double-throw slide switch type that switches between two high-frequency signal paths in accordance with the development steps.

Figure 1 shows the contact switching section of the high frequency signal switching device at the first stage of development in this invention.
6 and 17 are planted in a straight line, and bridge-shaped contact pieces 2 and 3 are placed in a slidable state so as to cross one terminal. Here, the basic configuration for a single-pole, double-throw signal switch may be as shown in FIG. A circuit diagram at this time is shown in FIG. Therefore, in FIG.
Reference numerals 5 and 17 are grounding terminals that are not placed directly to form a transmission path, but are placed primarily for high-frequency effects, and are secondarily used to prevent the bridge contact pieces 2 and 3 from coming off when sliding. It also has the role of preventing. Also in FIG. 1, the bridge contact piece 3
is in contact with the transmission terminals 14 and 17 to transmit high frequency signals, and the bridge contact piece 2 is arranged for high frequency effects. When the first contact state is switched to the second contact state, the bridge contact piece 2 contacts the transmission terminals 12 and 14 to transmit a high frequency signal, and the bridge contact piece 3 exhibits a high frequency effect.

FIG. 4 shows a circuit diagram showing the basics of the present invention.
When a high-frequency signal system, . →
It is transmitted from terminal 14 to the signal system. At this time, if measures are not taken to prevent high-frequency signal leakage, impedance mainly due to minute stray capacitances will be formed in a complicated manner between terminals 14 and 12, and signals will be transmitted to terminal 12, which is open. It leaks and is guided into the signal system, reducing isolation and causing harm to the signal system. Incidentally, if the signal system is an antenna circuit, the leaked high-frequency signal will be radiated as unnecessary radiation and cause radio wave interference in the vicinity.

In the present invention, in order to minimize leakage due to electrostatic coupling and electromagnetic coupling of high frequency signals at the switch part, the bridge contact piece 2 is connected to the grounding terminal 11 so as to cover the transmission terminal 12 connected to the signal system. 13
are arranged as pier ground terminals, and then the pier ground terminals 11 and 13 are electrically connected to the support legs of the high-frequency ground potential portion of the metal frame 5 or the caulked portion thereof. All of the pier ground terminals 11, 13, 15, and 17 may be grounded, or only one pair of them may be grounded.

FIG. 5 is an external perspective view showing the high frequency signal switching device at the second stage of development of the present invention, and is a control body that holds the pier ground terminals 11, 13 and the bridge contact pieces 2, 3 and switches the transmission path. When the bridge contact piece comes to the second contact position due to a certain sliding body 4, the pier terminal 15 on the open side when the signal system and the signal system are connected via the bridge contact piece 2' shown in FIG. 17 is bent into an L-shape and fitted into a concave support leg provided by extending a part of the side surface of the metal frame 5, and is electrically connected. Note that the transmission terminals 12, 14, 16 and the pier ground terminals 11, 13, 15, 17 are installed in a straight line.

Figure 6 shows an example of the third development stage, which attempts to obtain isolation of about 60 dB or more even in the UHF band. A shield plate 6 exceeding the height and having a width larger than the width of the frame 5 is electrically connected, and at the same time, the shield plate 6 is also electrically connected to the metal frame 5. The other pier ground terminals 11 and 17 are each electrically connected to the frame 5 to form a closed circuit with the bridge contact piece and shield the open terminal. 7th
The figure is an external perspective view of the example of the circuit diagram shown in FIG. Also in FIG. 7, the transmission terminal and the pier ground terminal are installed in a straight line.

FIG. 8 shows a high-frequency signal switching device at the final stage of the present invention, in which coaxial connectors 8, 9, and 10 are arranged on a metal cover 7 to realize the high-frequency signal switching device. In this case, in addition to improving isolation, it is also possible to match the characteristic impedance and prevent unnecessary radiation from the terminal itself to the outside. In the same figure, the outer conductors of the coaxial plugs 8, 9, and 10 are electrically connected to the metal cover 7, and the metal cover 7 is also connected to the metal frame 5, shield plate 6, and pier ground terminals 11, 13, 15, and Connected to connect the same potential of ground.

FIG. 9 shows a side plate 23 fitted into the metal cover 7.
In this embodiment, the claw part 24 is fitted into the fitting hole 22 protruding from the side surface of the metal cover 5, and the claw part 24 is fitted into the fitting hole 22 projecting from the side surface of the metal cover 5.
is fitted into the protrusion of the shield plate 6 and electrically connected.

Figure 10 shows frequency-separation characteristics, where curve A shows an example of the characteristics of a recently developed high frequency signal switch, curve B shows the characteristics of the high frequency signal switch according to the present invention, and the characteristic diagram is 300MHz～
This shows that a significant isolation improvement of about 10 to 20 dB can be achieved in the 1000 MHz UHF band.

The effects achieved by the present invention described above are as follows: a. In the high frequency range from the VHF band to the UHF band, coupling between terminals inside the frame, which had been ignored in the past, is significantly reduced, making it possible to improve the conventional high-performance high-frequency signal switching. 10 more in the UHF band compared to the device
Improves isolation by ~20dB and completely prevents unnecessary radiation. In other words, when one contact piece establishes continuity between the transmission terminals, the other contact piece bridges between the ground terminals and is shielded by covering the transmission terminal provided between the ground terminals. It is possible to prevent electrostatic coupling with the transmission terminal in the state, and also to prevent high frequency signals from directly entering the transmission line side, thereby achieving high isolation.

b In order to implement this invention, it is only necessary to increase the number of bridge contact pieces and pier ground terminals, as well as increase the number of soldering points accordingly, and it achieves an extremely large effect with a small increase in cost and man-hours, and is inexpensive and high-performance. A high-performance high-frequency signal switching device can be provided, which is extremely useful in practice.

c. By implementing the present invention, it is possible to provide a small, lightweight, and thin high-frequency signal switch without significantly increasing the size or increasing the weight.

d Furthermore, by using the present invention, a high frequency signal switching device having a larger number of switching circuits can be easily realized.

As described above, the present invention can easily ensure the required isolation and at the same time improve the quality of high frequency signal transmission, and is of great industrial value.

[Brief explanation of drawings]

Figure 1 is a perspective view of the switching unit showing the basic concept of the high frequency signal switch in the present invention, Figure 2 is a perspective view showing the basic configuration of a single pole double throw signal switch, and Figure 3 is the same circuit. Figure 4 is a circuit diagram at the development stage according to the present invention, Figure 5 is an external perspective view of the same high frequency signal switching device, Figure 6 is a circuit diagram when a shield plate is added, and Figure 7 is the same shield plate. 8 is a perspective view of the main part of the high frequency signal switching device of the present invention when a coaxial plug is attached. FIG. 9 is a perspective view of the side plate of the same embodiment. The figure is a frequency-isolation comparison diagram between the high frequency signal switch of the present invention and a recently developed one. 1... Terminal board, 2, 3... Contact piece, 4... Control body, 5... Frame, 6... Shield plate, 7...
Metal cover, 8 to 10... Coaxial plug, 11 to 21
...Terminal.

Claims (1)

[Scope of utility model registration request] A large number of terminals are installed in a straight line on the terminal board so that there are ground terminals on both sides of the terminals forming the transmission path, and when one conducts between the transmission terminals on this terminal board, the other a control body that drives and controls at least two contact pieces that act to bridge the ground terminals across the ground terminals and shield the transmission terminal between the ground terminals, and is placed over the terminal board. At least one of the ground terminals bridged by the contact piece is electrically connected to the frame, and a shield plate electrically connected to the ground terminal is electrically connected to the frame, and the lower surface of the terminal board is electrically connected to the frame. A high-frequency signal switching device that has a metal cover attached, a coaxial plug connected to the transmission terminal, and an electrical connection between the frame and the metal cover.