JPS5924204Y2 - wireless communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wireless communication device equipped with an antenna duplexer for using one antenna as both a transmitter and a receiver when the transmitting frequency and the receiving frequency are different.

In general, an antenna duplexer uses one antenna for both a receiver and a transmitter, and in order to minimize the loss caused by the sharing, it is a bandpass filter or a bandstop filter. It is used in combination with railway lines.

Conventionally, coaxial lines are used as distributed constant lines for use in this type of antenna duplexer, which has the disadvantage of increasing the size and the number of components such as connectors and T-branches.

In particular, there was a drawback that there were a large number of devices including filters for local oscillation signals connected to the mixer of the receiver.

An object of the present invention is to provide a wireless communication device that eliminates these conventional drawbacks.

This will be explained below with reference to the drawings.

FIG. 1 is an example of a conventional radio device equipped with an antenna duplexer.

In FIG. 1, 1 indicates an antenna duplexer, and a transmitter 11
The transmission signal generated by
is supplied to

The received signal received by the antenna 15 is transmitted to the air duplexer 1
The signal is supplied to the mixer 17 of the receiver through the distributed constant line C2, the bandpass filter 13, and the distributed constant line C3.

The local oscillation signal generated by the local oscillator 16 is supplied to the mixer 17 through the bandpass filter 14 in the antenna duplexer 1 and the distributed constant line C4.

The mixer 17 mixes the local oscillation signal and the received signal using the nonlinear characteristics of the mixer 17 to generate an intermediate frequency signal.

The intermediate frequency signal generated by the mixer 17 is sent to the intermediate frequency section 1.
8, the signal is amplified and detected, and is supplied to the low frequency section 19.

One low frequency section amplifies the detected received signal and drives a speaker or the like.

Here, distributed constant lines C1 and C4 have a length of a half wavelength of the receiving frequency or an odd number multiple thereof, C2 has a length of a half wavelength of the transmitting frequency or an odd number multiple thereof, and C3 has a length of a half wavelength of the local oscillation frequency or an odd number multiple thereof. It is long.

For example, look at the transmitting side, that is, the bandpass filter 12 from the point of the T-branch T1.

Since the center frequency of the bandpass filter 12 is the transmission frequency, the impedance of the bandpass filter 12 is approximately O at the reception frequency.

On the other hand, if the length of the distributed constant line C1 is set to the Kei wavelength of the receiving frequency or an odd multiple thereof, the impedance at the T-branch T1 will be extremely high.

Therefore, the transmitting side has almost no influence on the received signal passing through the T-branch T1.

When looking at the receiver side, that is, the bandpass filter 13 side from the point of T-branch T1, the impedance at the point of T-branch T1 at the transmission frequency is very high as described above, and the influence of the receiving side on the passage of the transmitted signal is almost none.

The explanation of T-branch T2 is the same as described above, and will therefore be omitted.

As explained above, the transmission signal is supplied to the antenna 15 through the antenna duplexer 1 without being affected by the receiving side,
The received signal received by the antenna 15 is supplied to the mixer 17 without being influenced by the transmitting side and the local oscillator side in the antenna duplexer 1, that is, the bandpass filter 14 and the local oscillator 16.
The local oscillation signal is supplied to the mixer 17 without being influenced by the bandpass filter 13, the antenna 15, and the transmitting side.

Such conventional radio equipment equipped with an antenna duplexer has the above-mentioned drawbacks.

Next, the present invention will be explained.

FIG. 2 shows a stripline directional filter used in the present invention.

In FIG. 2, 20 to 23 are input/output terminals, 24 is a one-wavelength loop resonator, and 25 and 26 are half-wavelength directional couplers.

Here, the length of 24 is assumed to be one wavelength of frequency f.

When a signal of frequency f is input from terminal 20, this signal appears only from terminal 22 and does not appear from other terminals 21 and 23.

Conversely, when this signal is input to terminal 21, it appears only from terminal 23 and does not appear from the other terminals 20 and 22.

The same thing will happen if the input is made from the terminal 22 or 23.

On the other hand, when the signal frequency is different from the tuning frequency f of the loop resonator, the signal input to the terminal 20 appears at the terminal 21 and does not appear at the other terminals 22, 23.

The same thing can be said when inputting from terminals 21, 22 or 23.

An example of a directional filter is the book MICROWAVE FILTER 3, IMPEDAN by G. L. MATTHAEI.
CE-MA-TCHING NETWORKSA
NDCOUPLINGSTRUCTURES(MCGR
AW-HILLBooK COMPANY, No. 867-8
(page 72), etc.

FIG. 3 is a reference diagram related to the present invention.

In FIG. 3, 2 indicates an antenna duplexer, and terminals 20 to 23 in the antenna duplexer 2 are input/output terminals of a directional filter;
24 is a one-wavelength loop resonator tuned to the receiving frequency fR.

The transmission frequency is f. Then, the fT signal output from the transmitter is connected to the terminal 20.

Since the loop resonator 24 is tuned to the reception frequency fR, all the transmission signals of fl supplied to the terminal 20 are transmitted to the terminal 2.
1 and is supplied to the antenna 15.

The received signal received by the antenna 15 is transmitted to the loop resonator 24.
is tuned to the receiving frequency, so terminal 21 to terminal 23
is supplied to the mixer 17 through.

A local oscillation signal generated by the local oscillation section 16 is supplied to a terminal 22.

Since the tuning frequency fR of the loop resonator and the local oscillation signal frequency are different, the local oscillation signal is supplied to the mixer 17 through the terminal 23.

17 to generate an intermediate frequency signal.

FIG. 4 shows an embodiment of the present invention.

In FIG. 4, 3 indicates an antenna duplexer, 20 to 23 in the antenna duplexer 3, 30 to 33 are input/output terminals of the directional filter, and 40.degree. 41 is a terminating resistor.

24 and 34 are each one wavelength loop resonator;
is tuned to the reception frequency fR, and 34 is tuned to the local oscillation frequency f.

When the transmission frequency is fl, the fT signal output from the transmitter is connected to the terminal 20.

Since the loop resonator 24 is tuned to the reception frequency fR, all the transmission signals of the f unit supplied to the terminal 20 are transmitted to the terminal 2.
1 and is supplied to the antenna 15.

The received signal received by the antenna 15 is outputted to the terminal 23 through the terminal 21 because the loop resonator 24 is tuned to the receiving frequency fR.

The loop resonator 34 has a local oscillation frequency f1. Since the received signal is tuned to , the received signal is supplied from terminal 30 to mixer 17 through terminal 31.

Since the loop resonator 34 is tuned to the local oscillation frequency f, the local oscillation signal from the local oscillation section is supplied to the mixer 17 from the terminal 33 through the terminal 31.

The mixer 17 mixes the local oscillation signal and the received signal using the nonlinear characteristics of the mixer 17 to generate an intermediate frequency signal.

It is clear that the directional filter used in the present invention is not limited to a directional filter having only one loop resonator, but may also be a directional filter having multiple loop resonators. be.

As explained above, constructing an antenna duplexer using a directional filter simplifies the shape of the antenna duplexer compared to a conventional antenna duplexer that combines a bandpass filter and a half-wavelength distributed constant line. The number of parts can be reduced, making it compact and economical.

Moreover, it has an excellent feature of extremely low loss due to the characteristics of a directional filter.

[Brief explanation of the drawing]

Figure 1 is an example of a conventional wireless communication device, Figure 2 is a directional filter used in the present invention, Figure 3 is a reference diagram related to the present invention, and Figure 4 is a wireless communication device according to the present invention. 1 is a diagram showing an example of a machine. In the figure, 1, 2.3... Antenna duplexer, 1
1...Transmitter, 12,13.14...
Bandpass filter, 15...Antenna, 16...
・Local oscillation section, 17...Mixer, 18...
...Intermediate frequency section, 19...Low frequency section, 24.3
4...-Wavelength loop resonator, 20-23.30
~33...Input/output terminal of directional filter, 40.
41...Terminal resistor.

Claims (1)

[Scope of utility model registration request] In a wireless communication device including a transmitter, an antenna, a local oscillator, a mixer, and an antenna duplexer coupled to these, the antenna duplexer is configured with first and second stripline directional filters. and a first stripline connecting each of the directional filters between a first terminal and a second terminal, a second stripline connecting a third terminal and a fourth terminal, a loop resonator provided between the first stripline and the second stripline and coupled to the first and second striplines, the first stripline type directional filter; A loop resonator of the second stripline directional filter is tuned to the oscillation frequency of the local oscillator, and a loop resonator of the second stripline directional filter is tuned to the oscillation frequency of the local oscillator. first, second and third terminals of the stripline directional filter are connected to the transmitter, the antenna and a first terminator, respectively; first, second and fourth terminals are connected to a second terminator, the local oscillator and the mixer; a fourth terminal of the first stripline directional filter is connected to the second terminator; A wireless communication device, characterized in that it is connected to the third terminal of a stripline directional filter.