Wireless apparatus

The present invention relates to a wireless device, and particularly to a transmission technique suitable for a high frequency band of 30 GHz or higher.

In recent years, research on communication technologies using the quasi-millimeter wave frequency band of 30 GHz or higher and the millimeter wave frequency band has become active. In such a high frequency band, it is difficult to generate a stable local oscillation frequency. Unless stable local oscillation frequencies are provided on the transmitting side and the receiving side, it is difficult to realize high-quality communication.

Patent Document 1 discloses a technique of transmitting an unmodulated carrier having a local oscillation frequency together with a radio-modulated signal. On the receiving side, the received unmodulated carrier is used as the local oscillation frequency to demodulate the radio-modulated signal. Since it is not necessary to provide a high-precision local oscillator on the receiving side, the configuration of the receiving device can be simplified. In addition, when the unmodulated carrier and the wireless modulation carrier are affected by the same environmental factor (for example, temperature fluctuation), the effect of the environmental factor (for example, for example) can be achieved by demodulating using the received unmodulated carrier. Fluctuations due to temperature fluctuations) can be offset, and good communication quality can be provided.<patcit num="1"><text>Japanese Unexamined Patent Publication No. 2001-53640</text></patcit>

<p> However, the invention described in Patent Document 1 has a problem that a stable radio-modulated carrier cannot be generated because it uses a local oscillator that generates the same oscillation frequency as the unmodulated carrier output by the antenna. .. Local oscillators, which have the ability to oscillate stably at oscillation frequencies of 30 GHz or higher, have many problems that must be solved by current technology. In particular, manufacturing a 60 GHz local oscillator required to realize millimeter-wave wireless communication in the 60 GHz band, which has been attracting attention recently, requires extremely advanced technology and is extremely expensive.</p><p> Therefore, an object of the present invention is to provide a wireless device capable of realizing wireless communication using a high frequency band of 30 GHz or higher, which is difficult to generate a stable local oscillation frequency, with an inexpensive and simple configuration. To do.</p>

<p> In the present invention, as described in claim 1, the local oscillator, the amplifier that amplifies the output signal of the local oscillator and outputs the local oscillation frequency and its harmonic components, and the output and information signal of the amplifier are input. The wireless device has a harmonic mixer that passes through the high-frequency component of the output of the amplifier and internally generates an up-convert signal of the information signal with a harmonic component based on the local oscillation frequency. By generating a harmonic component with an amplifier and outputting it through a harmonic mixer, the harmonic component of the output signal of the local oscillator can be transmitted together with the up-conversion signal. The local oscillator only needs to be able to oscillate a low frequency, and wireless communication using a high frequency band of 30 GHz or higher can be realized with an inexpensive and simple configuration.</p><p> The invention according to claim 2 is the invention according to claim 1, wherein the harmonic mixer includes an anti-parallel diode, the output signal of the amplifier is given to one end thereof, and the information signal is given to the other end. It is a wireless device that extracts the output signal of the harmonic mixer from the end.</p><p> The invention according to claim 3 is the invention according to claim 1, wherein the harmonic mixer includes an anti-parallel diode, the output signal of the amplifier is given to one end thereof, and the information signal is given to the other end. This is a wireless device in which the output signal of the harmonic mixer is taken out from the end and an open stub having a length of 1/4 of the wavelength of the harmonic component is connected to the other end.</p><p> The invention according to claim 4 is the invention according to claim 1, wherein the harmonic mixer includes an anti-parallel diode, the output signal of the amplifier is given to one end thereof, and the information signal is given to the other end. This is a wireless device in which the output signal of the harmonic mixer is taken out from the end and a short stub having a length of 1/4 of the wavelength of the up-conversion signal is connected to the one end.</p><p> The invention according to claim 5 is the invention according to claim 1, wherein the harmonic mixer includes an anti-parallel diode, the output signal of the amplifier is given to one end thereof, and the information signal is given to the other end. The output signal of the harmonic mixer is taken out from the end, and an open stub having a length of 1/4 of the wavelength of the harmonic component is connected to the other end to have a length of 1/4 of the wavelength of the up-convert signal. A wireless device in which a short stub is connected to one end.</p><p> The invention according to claim 6 is the invention according to claim 4 or 5, wherein the short stub has a length of 1/4 of a wavelength corresponding to the center frequency of at least one sideband of the up-convert signal. It is a wireless device having.</p><p> The invention according to claim 7 is the wireless device according to any one of claims 1 to 7, wherein the amplifier has a frequency band of an output signal of the local oscillator located in both a linear region and a saturation region of gain. It is a wireless device having a configuration to be used.</p><p> The invention according to claim 8 is the wireless device according to any one of claims 1 to 8, wherein the wireless device further includes an amplifier that linearly amplifies the harmonics.</p><p> The present invention also comprises a local oscillator, an amplifier that amplifies the output signal of the local oscillator and outputs a signal containing its harmonic components, and an output signal and an information signal of the local oscillator. It is a wireless device having a harmonic mixer that inputs and outputs an up-convert signal of the information signal.</p><p> The invention according to claim 10 is the wireless device according to claim 9, wherein the output signal of the amplifier is combined with the output signal of the harmonic mixer.</p><p> The invention according to claim 11 is the wireless device according to claim 9 or 10, wherein the first external connection terminal that receives the output signal of the harmonic mixer and the second external connection terminal that receives the output of the amplifier. It is a wireless device to have.</p><p> The invention according to claim 12 is the wireless device according to any one of claims 9 to 11, wherein a bandpass filter is provided after the amplifier.</p><p> The invention according to claim 13 is the wireless device according to any one of claims 9 to 12, wherein the harmonic mixer includes an anti-parallel diode, one end of which is given an output signal of the local oscillator, and the other end. This is a wireless device that gives the information signal to the device and extracts the output signal of the harmonic mixer from the other end.</p><p> The invention according to claim 14 is the wireless device according to any one of claims 9 to 12, wherein the harmonic mixer includes an anti-parallel diode, one end of which is given an output signal of the local oscillator, and the other end. The information signal is given to the other end, the output signal of the harmonic mixer is taken out from the other end, and an open stub having a length of 1/4 of the wavelength of the harmonic component is connected to the other end.</p><p> The invention according to claim 15 is the wireless device according to any one of claims 9 to 12, wherein the harmonic mixer includes an anti-parallel diode, one end of which is given an output signal of the local oscillator, and the other end. The information signal is given to the above, the output signal of the harmonic mixer is taken out from the other end, and a short stub having a length of 1/4 of the wavelength of the up-conversion signal is connected to the one end.</p><p> The invention according to claim 16 is the wireless device according to any one of claims 9 to 12, wherein the harmonic mixer includes an anti-parallel diode, one end thereof is provided with an output signal of the local oscillator, and the other end is provided. The information signal is given to the other end, the output signal of the harmonic mixer is taken out from the other end, and an open stub having a length of 1/4 of the wavelength of the harmonic component is connected to the other end to obtain the up-conversion signal. A short stub having a length of 1/4 of the wavelength is connected to the one end.</p><p> The invention according to claim 17 is the wireless device according to any one of claims 1 to 16, wherein the harmonic is a second harmonic of an output signal of the local oscillator.</p><p> The invention according to claim 18 is the wireless device according to any one of claims 1 to 17, wherein a power amplifier is provided after the harmonic mixer.</p>

<p> It is possible to provide a wireless device capable of realizing wireless communication using a high frequency band of 30 GHz or higher, which is difficult to generate a stable local oscillation frequency, with an inexpensive and simple configuration.</p>

Hereinafter, examples of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a configuration of a wireless device 100 according to a first embodiment of the present invention. The radio device 100 includes a harmonic mixer 20, a local oscillator 22, an amplifier 24, a power amplifier 26, and an external connection terminal 29. The local oscillator 22 has a frequency f_LOGenerates a local oscillation signal. The amplifier 24 has a configuration in which the frequency band of the oscillation output signal of the local oscillator 22 is located in both the linear region and the saturation region of the gain. FIG. 2 shows the input / output characteristics of the amplifier 24. The oscillation output signal of the local oscillator 22 is amplified using both the linear region and the saturation region in the figure. As shown in FIG. 3A, this oscillation output becomes a distorted signal S2 with respect to the linearly amplified signal S1. This distorted signal S2 has a frequency f as shown in the spectrum diagram of FIG. 3 (b)._LOIn addition to the fundamental wave of, it contains harmonic components such as the second harmonic and the third harmonic. Below, the frequency components of the output signal of the amplifier 24 are n · f_LOIt is represented by (n is a positive natural number). The output signal of the amplifier 24 is given to the first terminal of the harmonic mixer 20. The second terminal of the harmonic mixer 20 has a frequency f_IFThe information signal IF of is given. The harmonic mixer 20 has a frequency component f included in the output signal of the amplifier 24._LON harmonics n f_LOIs generated to combine this harmonic component with the information signal IF, and the harmonic components n · f included in the output signal of the amplifier 24_LOPass as it is.

In the following, for the sake of simplicity, the frequency f of the output signals of the amplifier 24_LOFundamental wave (local oscillation signal) and second harmonic (frequency 2f)_LO) Only, the harmonic mixer 20 is the fundamental wave f_LOConsider the case where only the double wave of is generated. The harmonic mixer 20 is the fundamental wave f from the amplifier 24._LO2nd harmonic 2f_LOIs generated, and this is combined with the information signal IF to up-convert the frequency 2f._LO± f_IFAnd the second harmonic 2f from the amplifier 24_LOPass as it is. That is, the output signal of the harmonic mixer 20 has a frequency of 2f._LOSignal and frequency 2f_LO± f_IFIt is a superposition of the signals of. In other words, the output of the harmonic mixer 20 has a frequency of 2f._LOThe signal component and frequency of (2f)_LO± f_IF) Is included. If 2 is replaced with n and used as a general notation, the output of the harmonic mixer 20 is n · f._LOFrequency components and (n f_LO± f_IF) Includes frequency components.

Figure 4 shows the frequency spectrum of the output signal of the harmonic mixer 20. Frequency n f in the center of the figure_LOThe signal of is the signal passed through the harmonic mixer 20 from the amplifier 24, and the center frequency of the right sideband is n · f._LO+ f_IFThe center frequency of the left sideband is n f._LO-f_IFIs. Now f_LO= 30GHz, f_IFIf = 5GHz, n = 2, the harmonic mixer 20 includes a 60GHz signal, a 65GHz radio modulation signal, and a 55GHz radio modulation signal. This 60 GHz signal becomes a local oscillation signal for antenna output, and is transmitted to the air via the amplifier 26, the external connection terminal 29, and the antenna 40 together with the two modulated signals.

The harmonic component generated by the amplifier 24 is input to the harmonic mixer 20. Here, in the harmonic mixer 20, it is considered that this harmonic component generates a higher frequency by the action of the harmonic mixer 20, which is mixed with the information signal IF. However, in reality, the intensity (power) of the harmonic components input to the harmonic mixer 20 becomes smaller as the order increases, and the harmonic mixer 20 cannot be driven sufficiently. Therefore, regarding the input of these higher frequencies, There is no substantial effect.

In addition, the harmonic component generated by the amplifier 24 passes through the harmonic mixer 20, but the frequency of the second harmonic is close to the mixing frequency (target frequency) output from the harmonic mixer 20, so it is final. Is output to the outside. On the other hand, frequencies of 3rd harmonic or higher have low intensity from the beginning and are also outside the permissible frequency of the circuit in the subsequent stage, so that there is no substantial effect on operation.

According to this embodiment, even though one local oscillator 22 is used, its oscillation frequency f_LON times the frequency n f_LOIt is possible to generate and output a local oscillation signal for antenna transmission. In other words, a local oscillator 22 having an oscillation frequency of 1 / n of the desired local oscillation frequency for antenna output may be prepared. In the case of the above example, a 30 GHz local oscillator 22 may be prepared. Therefore, wireless communication 100 suitable for a high frequency band of 30 GHz or more can be realized inexpensively and easily. Further, since both the locally oscillating signal for antenna output and the radio modulation signal pass through the harmonic mixer 20, they are similarly affected by the fluctuations in the harmonic mixer 20. Therefore, the fluctuation generated in the harmonic mixer 20 can be offset by the demodulation processing on the receiving side using the local oscillation frequency for antenna output.

As can be seen from the above explanation, the power amplifier 26 has an oscillation frequency f._LON times the frequency n f_LOSince it is not involved in the operation of generating the above, it can be omitted if necessary.

FIG. 5 is a circuit diagram showing a configuration example of the harmonic mixer 20. The circuit shown shows a state in which circuit components are connected using an ideal line in order to make the figure easy to understand. The harmonic mixer 20 has an anti-parallel diode (hereinafter abbreviated as APDP) 202. APDP202 has a configuration in which two diodes D1 and D2 are connected in parallel in opposite directions. APDP202 has the current and voltage characteristics as shown in FIG. Harmonics of the input signal are generated by using the non-linear part of the current / voltage characteristics. The output signal of the amplifier 24 is given to one end of the APDP202 via the external connection terminal 214. Below, for the sake of simplicity, the 30 GHz fundamental wave n f_LO(n = 1) and 60GHz second harmonic n · f_LOConsider only (n = 2). An information signal IF is given to the other end of the APDP202 via an external connection terminal 210, a decoupling capacitor C3, and a low-pass filter 208. As an example, the frequency of the information signal IF is ± 5 GHz. The low-pass filter 208 has two capacitors C1 and C2 and an inductor L1. The open stub 204 and the short stub 206 are provided to suppress signal loss and improve efficiency, and are provided as needed.

Now, the operation in the state where the open stub 204 and the short stub 206 are not connected will be described. APDP202 uses the non-linear part of the input / output characteristics shown in FIG. 6 to generate a second harmonic 60 GHz with a local oscillation frequency of 30 GHz given to one end. At the other end of APDP202, ± 5 GHz of the information signal IF is mixed with this 60 GHz, and the 65 GHz wireless modulation signal and the 55 GHz wireless modulation signal are output to the outside via the external connection terminal 29. Further, the 60 GHz signal, which is the second harmonic from the amplifier 24, passes through APDP202 and is given to the external output terminal 29. As a result, a 60 GHz signal, a 65 GHz signal, and a 55 GHz signal are output to the output terminal 29. The 60 GHz signal is output as an antenna output local oscillation signal to the air via the antenna 40 (Fig. 1) together with the 55 GHz and 65 GHz radio modulation signals.

Preferably, as shown in FIG. 5, the open stub 204 and the short stub 206 are provided. The open stub 204 is connected to the output side of the APDP202 and has a local oscillation frequency f of the local oscillator 22._LOIt has a length of 1/4 of the wavelength corresponding to. Therefore, the local oscillation frequency f_LOFor signals (30 GHz in the example just described), the open end of the open stub 204 acts as ground. As a result, a 30 GHz signal is efficiently applied between both ends of the APDP202. The open stub 204 is not visible for 60GHz signals. The short stub 206 is connected to the input side of APDP202, and the radio modulation signal 2f_LO± f_IFIt has a length of 1/4 of the wavelength corresponding to any frequency (55 GHz and 65 GHz in the above example). For example, if the short stub 206 has a length of 1/4 of the wavelength of the 65 GHz radio modulation signal, the 65 GHz radio modulation signal is efficiently applied between the input side end of the APDP202 and the ground, so that the 65 GHz radio modulation signal The radio modulation signal can be folded back to the APDP202 side. Of course, the short stub 206 may have a configuration having a length of 1 / 4n of the wavelength of the 55 GHz radio modulation signal. The radio-modulated signal can transmit a two-sided wave or only one of them. If you want to send only one, you only need one short stub 206. When both are transmitted, it is preferable to further provide a short stub 208 as shown in FIG. 7 to support both 55 MHz and 65 MHz radio modulation signals.

As described above, the harmonic mixer 20 shown in FIG. 5 can pass through the local oscillation frequency for antenna output and can efficiently generate a radio modulation signal.

If necessary, the bandpass filter 28 may be provided after the harmonic mixer 20 as shown in FIG. 8A. The bandpass filter 28 can remove unnecessary frequency components. Further, when the level of the harmonic component output by the amplifier 24, particularly the second harmonic component, is insufficient, the amplifier 24A that linearly amplifies the second harmonic may be connected to the subsequent stage of the amplifier 24. Further, the gain of the amplifier 24A may be variable. In addition, a bandpass filter is provided after the amplifier 24, and the local oscillation frequency f_LOAnd second harmonic 2 f_LOIt may be configured to supply only the harmonic mixer 20.

FIG. 9 is a block diagram of the wireless device 200 according to the second embodiment of the present invention. In the figure, the same components as those described above are given the same reference numbers. The radio device 200 includes a harmonic mixer 20, a local oscillator 22, an amplifier 24, a bandpass filter 28, a power amplifier 26, and an external connection terminal 29. The output signal of the local oscillator 22 is directly supplied to the harmonic mixer 20, and is also branched and supplied to the amplifier 24. The harmonic mixer 20 has frequency components n · f included in the output signal of the amplifier 24._LOThe n-fold wave of is generated, and this n-fold wave and the information signal IF are combined. Therefore, unlike the harmonic mixer 20 in FIG. 1, the output frequency of the harmonic mixer 20 in FIG. 9 is n · f._LO± f_IFIs. This output signal passes through the bandpass filter 28 and is given to the power amplifier 26. The amplifier 24 has a configuration in which the frequency band of the oscillation output signal of the local oscillator 22 is located in both the linear region and the saturation region of the gain, and the output signal is n · f._LOIt has a frequency component of (n = 1, 2, ...). That is, the output signal of the amplifier 24 has a local oscillation frequency f._LOAnd its harmonic components n f_LOincluding. The output signal of the amplifier 24 is combined with the output signal of the harmonic mixer 20 passing through the bandpass filter 28. Therefore, the power amplifier 26 has frequencies n · f._LOSignal and frequency n f_LO± f_IFThe signal of is amplified by power, and the output signal is transmitted via the antenna 40 connected to the external connection terminal 29.

In this way, the wireless device 200 inputs the local oscillator 22, the amplifier 24 that amplifies the output signal of the local oscillator and outputs a signal including its harmonic component, and the output signal and the information signal IF of the local oscillator 24. It has a configuration provided with a harmonic mixer 20 that mixes and outputs an up-convert signal of the information signal, and has the same effect as that of the first embodiment.

Instead of the configuration of FIG. 9, as shown in FIG. 10, the output of the amplifier 24 can be transmitted by using an antenna 50 different from the antenna 40. That is, the local oscillation signal for antenna transmission may be transmitted by using an antenna different from the wireless modulation. The antenna 50 is connected to the external connection terminal 39.

Further, as shown in FIG. 11, an amplifier 24B that linearly amplifies the output of the local oscillator 22 may be interposed to amplify the output to a desired level and output it to the harmonic mixer 20. In this case, a bandpass filter is provided after the amplifier 24B, and the local oscillation frequency f_LOOnly may be configured to supply the harmonic mixer 20. Further, as shown in FIG. 12, a bandpass filter 36 may be provided after the amplifier 24 to remove unnecessary waves. For example, the bandpass filter 36 is 2f_LOIt is intended to pass only.

The two examples of the present invention and their modifications have been described above. The present invention is not limited to these, and includes other examples and modifications.

<figref num="1">It is a block diagram of the wireless device which concerns on Example 1 of this invention.</figref><figref num="2">It is a graph which shows the input / output characteristic of the amplifier 24 shown in FIG.</figref><figref num="3">It is a figure which shows the output signal waveform and the frequency spectrum of the amplifier 24 shown in FIG.</figref><figref num="4">It is a figure which shows the frequency spectrum of the output signal of the harmonic mixer shown in FIG.</figref><figref num="5">It is a circuit diagram which shows one configuration example of the harmonic mixer shown in FIG.</figref><figref num="6">It is a graph which shows the voltage-current characteristic of the anti-parallel diode (APDA) used in the circuit of FIG.</figref><figref num="7">It is a circuit diagram which shows another configuration example of the harmonic mixer shown in FIG.</figref><figref num="8">It is a figure which shows the modification of the circuit structure shown in FIG.</figref><figref num="9">It is a block diagram of the wireless device which concerns on Example 2 of this invention.</figref><figref num="10">It is a block diagram which shows the modification of the structure shown in FIG.</figref><figref num="11">It is a block diagram which shows another modification of the structure shown in FIG.</figref><figref num="12">It is a block diagram which shows still another modification of the structure shown in FIG.</figref>

Code description

20 Harmonic Mixer 22 Local Oscillator 24, 24A, 24B Amplifier 26 Power Amplifier 210, 212, 214 External Connection Terminal 28 Bandpass Filter 32 Amplifier 36 Bandpass Filter 100, 200 Radio 204 Open Stub 206, 208 Short Stub