Frequency converter and frequency conversion method

Abstract

To achieve miniaturization of device and circuit size in a frequency converter while ensuring a wide bandwidth.SOLUTION: A frequency converter is a double-conversion frequency converter including: a first frequency converter that converts an RF signal in a first frequency band into an RF signal in an intermediate frequency band; and a second frequency converter that converts the RF signal in the intermediate frequency band into an RF signal in a second frequency band. The intermediate frequency band is higher than the first and second frequency bands.SELECTED DRAWING: Figure 22

Description

[Technical Field]

[0001] The present disclosure relates to a frequency converter and a method of frequency conversion. [Background technology]

[0002] A satellite has the function of receiving an RF (Radio Frequency) signal from a ground station via an uplink, frequency-converting the frequency band of the received RF signal, and transmitting the frequency-converted RF signal to another ground station via a downlink. For this reason, a satellite is provided with a frequency converter that frequency-converts an RF signal in the uplink frequency band to an RF signal in the downlink frequency band.

[0003] One example of a conversion method used by a frequency converter is a single-conversion method in which an RF signal in an uplink frequency band is directly converted into an RF signal in a downlink frequency band.

[0004] However, in single-conversion frequency converters, harmonic components of the local oscillator signal (hereinafter referred to as LO (Local Oscillator) signal) used for frequency conversion are output as spurious signals, which may appear in the downlink frequency band. In this case, the frequency band near where the spurious signals appear becomes unusable for communication.

[0005] For this reason, in recent years, double conversion frequency converters that convert RF signals in the uplink frequency band via an intermediate frequency (IF) band into RF signals in the downlink frequency band have become mainstream (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-150884 Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, in a double-conversion frequency converter, a band lower than the uplink frequency band and the downlink frequency band is generally used as the IF band.

[0008] However, in double-conversion frequency converters, lowering the IF band poses problems such as the device and circuit size increasing due to the wavelength of the RF signal, and making it difficult to ensure a wide bandwidth.

[0009] In view of the above-mentioned problems, an object of the present disclosure is to provide a frequency converter and a frequency conversion method that can reduce the size of devices and circuits while ensuring a wide bandwidth. [Means for solving the problem]

[0010] According to one aspect, a frequency converter includes: A double-conversion frequency converter, a first frequency conversion unit that converts a radio frequency (RF) signal in a first frequency band into an RF signal in an intermediate frequency band; a second frequency conversion unit that converts the RF signal in the intermediate frequency band into an RF signal in a second frequency band, The intermediate frequency band is higher than the first frequency band and the second frequency band.

[0011] A frequency conversion method according to one aspect includes the steps of: A frequency conversion method performed by a double-conversion frequency converter, comprising: frequency converting a radio frequency (RF) signal in a first frequency band into an RF signal in an intermediate frequency band; frequency converting the RF signal in the intermediate frequency band into an RF signal in a second frequency band; The intermediate frequency band is higher than the first frequency band and the second frequency band. [Effects of the Invention]

[0012] According to the above-described aspect, it is possible to provide a frequency converter and a frequency conversion method that can reduce the size of the device and circuitry and ensure a wide bandwidth. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram illustrating a schematic configuration example of an artificial satellite and an example of frequency bands used by the artificial satellite for uplink and downlink. FIG. [Figure 2] FIG. 2 is a diagram illustrating an example of the characteristics of each frequency band used by an artificial satellite for uplink. [Figure 3] FIG. 2 is a diagram illustrating an example of the characteristics of each frequency band used by an artificial satellite for downlink. [Figure 4] FIG. 1 is a diagram illustrating a schematic configuration example of a single-conversion frequency converter according to a related art, which performs frequency conversion from V-band to Q-band. [Figure 5] 5 is a diagram schematically illustrating an example of harmonic components of an LO signal in the frequency converter shown in FIG. 4. FIG. [Figure 6] FIG. 1 is a diagram illustrating a schematic configuration example of a single-conversion frequency converter according to a related art, which performs frequency conversion from Ka band to K band. [Figure 7] 7 is a diagram schematically illustrating an example of harmonic components of an LO signal in the frequency converter shown in FIG. 6. FIG. [Figure 8] FIG. 1 is a diagram showing a schematic configuration example of a single-conversion frequency converter according to a related art, which performs frequency conversion from the Ku band (reception) to the Ku band (transmission). [Figure 9]9 is a diagram schematically illustrating an example of harmonic components of an LO signal in the frequency converter shown in FIG. 8. FIG. [Figure 10] FIG. 1 is a diagram illustrating a schematic configuration example of a frequency converter that performs frequency conversion from V band to Q band using a double conversion method according to a related art technique. [Figure 11] 11A and 11B are diagrams illustrating examples of harmonic components of an LO1 signal and an LO2 signal in the frequency converter shown in FIG. 10. [Figure 12] FIG. 1 is a diagram illustrating a schematic configuration example of a double-conversion frequency converter according to a related art, which performs frequency conversion from Ka band to K band. [Figure 13] 13 is a diagram schematically illustrating an example of harmonic components of an LO1 signal and an LO2 signal in the frequency converter shown in FIG. 12. FIG. [Figure 14] FIG. 1 is a diagram showing a schematic configuration example of a double-conversion frequency converter according to a related art, which performs frequency conversion from the Ku band (reception) to the Ku band (transmission). [Figure 15] 15 is a diagram schematically illustrating an example of harmonic components of an LO1 signal and an LO2 signal in the frequency converter shown in FIG. 14. FIG. [Figure 16] 1 is a diagram illustrating a schematic configuration example of a frequency converter that performs frequency conversion from V band to Q band using a double conversion method according to the present disclosure. FIG. [Figure 17] 17A and 17B are diagrams illustrating examples of harmonic components of an LO1 signal and an LO2 signal in the frequency converter illustrated in FIG. 16. [Figure 18] 1 is a diagram illustrating a schematic configuration example of a double-conversion frequency converter according to the present disclosure, which performs frequency conversion from Ka band to K band. [Figure 19] 19 is a diagram schematically illustrating an example of harmonic components of an LO1 signal and an LO2 signal in the frequency converter shown in FIG. 18. FIG. [Figure 20]1 is a diagram illustrating a schematic configuration example of a double-conversion frequency converter according to the present disclosure, which performs frequency conversion from the Ku band (reception) to the Ku band (transmission). [Figure 21] 21 is a diagram schematically illustrating an example of harmonic components of an LO1 signal and an LO2 signal in the frequency converter shown in FIG. 20. FIG. [Figure 22] FIG. 1 is a diagram illustrating a schematic configuration example of a double-conversion frequency converter according to the present disclosure. [Figure 23] FIG. 1 is a diagram illustrating a schematic configuration example of a computer that realizes part or all of the functions of a double-conversion frequency converter according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following description and drawings have been omitted and simplified as appropriate for clarity of explanation. In addition, in each of the following drawings, the same elements are given the same reference numerals, and duplicate explanations are omitted as necessary. Furthermore, specific numerical values ​​shown below are merely examples to facilitate understanding of the present disclosure, and are not limited thereto.

[0015] Before describing each embodiment of the present disclosure, related technologies and their problems will be described. <Related technologies and their challenges> FIG. 1 is a diagram showing a schematic configuration example of an artificial satellite and an example of frequency bands used by the artificial satellite for uplink and downlink.

[0016] As shown in FIG. 1, the satellite 10 has the function of receiving an RF signal from a ground station 20X via an uplink, frequency-converting the frequency band of the received RF signal, and transmitting the frequency-converted RF signal to a ground station 20Y via a downlink.

[0017] In order to realize the above functions, the satellite 10 is equipped with a receiving antenna 11, a frequency converter 12, satellite equipment 13, and a transmitting antenna 14. The receiving antenna 11 receives an RF signal in the uplink from the earth station 20X. The frequency converter 12 converts the RF signal in the uplink frequency band received by the receiving antenna 11 into an RF signal in the downlink frequency band. The intra-satellite device 13 performs various transmission processes such as amplifying the RF signal to a desired output level and adjusting the transmission timing of the RF signal in order to transmit the RF signal frequency-converted by the frequency converter 12 from the transmission antenna 14. Note that the transmission processes performed by the intra-satellite device 13 are not essential processes of the present disclosure, and therefore detailed description thereof will be omitted. The transmitting antenna 14 transmits the RF signal that has been subjected to transmission processing by the intra-satellite device 13 to the earth station 20Y via downlink.

[0018] Examples of uplink frequency bands used by the satellite 10 include the V band, Ka band, and Ku band (reception). Examples of downlink frequency bands used by the satellite 10 include the Q band, K band, and Ku band (transmission). Although frequencies below the Ku band (reception) are also used by satellites, this specification only exemplifies the Ku band and above, which handle wideband signals that are highly effective according to the present disclosure. The Ku band (reception) refers to 12.75 GHz-14.8 GHz, and the Ku band (transmission) refers to 10.7 GHz-12.75 GHz.

[0019] Fig. 2 is a diagram showing an example of the characteristics of each frequency band used by the satellite 10 in the uplink. Fig. 3 is a diagram showing an example of the characteristics of each frequency band used by the satellite 10 in the downlink. Specifically, in the examples of Figs. 2 and 3, the center frequency, bandwidth, and fractional bandwidth are shown as the characteristics of each frequency band. The fractional bandwidth is obtained by dividing the bandwidth by the center frequency. In other words, fractional bandwidth = bandwidth / center frequency.

[0020] For example, in the example of Figure 2, the Ka band and Ku band (reception) have the same fractional bandwidth, but the Ka band, which has a higher frequency band, has a wider bandwidth than the Ku band (reception). This shows that, if the fractional bandwidth is the same, the higher the frequency band, the wider the bandwidth can be secured.

[0021] For this reason, currently, satellite communications using the Ka band or Ku band (receiving) for uplink are mainstream, but recently, in order to expand satellite communications capacity, satellite communications using the V band for uplink and the Q band for downlink have been attracting attention.

[0022] The downlink frequency band is generally close to, but lower than, the uplink frequency band. Therefore, in satellite communications, when the Ka band is used for the uplink, the K band is generally used for the downlink. Also, in satellite communications, when the Ku band (receive) is used for the uplink, the Ku band (transmit) is generally used for the downlink.

[0023] Hereinafter, a frequency converter according to the related art, which is mounted on the artificial satellite 10 as the frequency converter 12, and the problems associated with it will be described. First, a single-conversion frequency converter according to the related art and its problems will be described below.

[0024] (1) Related Technology Issue 1 (1-1) Frequency conversion from V band to Q band FIG. 4 is a diagram showing a schematic configuration example of a single-conversion frequency converter 500 according to the related art, which performs frequency conversion from V-band to Q-band.

[0025] As shown in FIG. 4, the frequency converter 500 directly converts an uplink V-band RF signal into a downlink Q-band RF signal. The frequency converter 500 includes an LNA (Low Noise Amplifier) ​​501, an LO (Local Oscillator) 502, a mixer 503, and an MPA (Middle Power Amplifier) ​​504.

[0026] The LNA 501 amplifies the RF signal input from the receiving antenna 11 and outputs the amplified signal. The LO 502 generates an LO signal with an LO frequency of 9.7 GHz. Mixer 503 receives the RF signal output from LNA 501 and the LO signal generated by LO 502, and outputs an RF signal in a frequency band that is the difference frequency between the two signals. In this way, the LO 502 and the mixer 503 frequency convert (down-convert) the RF signal from the V band to the Q band. The MPA 504 amplifies the RF signal output from the mixer 503 and outputs it to the intra-satellite device 13 .

[0027] Fig. 5 is a diagram schematically showing an example of harmonic components of the LO signal in frequency converter 500 shown in Fig. 4. In Fig. 5, the horizontal axis represents frequency (the same applies to Figs. 7 and 9 below).

[0028] As shown in Figure 5, in frequency converter 500 that performs frequency conversion from V band to Q band, the LO frequency of the LO signal is 9.7 GHz. However, mixer 503 outputs not only the RF signal of the desired difference frequency, but also signals that are integer multiples of the frequencies of the input RF signal and LO signal as spurious signals. As a result, the quadruple LO signal (4LO) has a frequency of 9.7 x 4 = 38.8 GHz, which appears in the Q band's in-band. As a result, frequency bands around 38.8 GHz cannot be used for communication, limiting the available band.

[0029] (1-2) Frequency conversion from Ka band to K band FIG. 6 is a diagram showing a schematic configuration example of a single-conversion frequency converter 500A according to the related art, which performs frequency conversion from Ka band to K band.

[0030] As shown in FIG. 6, frequency converter 500A directly converts an uplink Ka-band RF signal into a downlink K-band RF signal. Frequency converter 500A differs from frequency converter 500 in that LO502 is replaced with LO502A. LO502A generates an LO signal with an LO frequency of 9.8 GHz.

[0031] FIG. 7 is a diagram schematically illustrating an example of harmonic components of the LO signal in frequency converter 500A shown in FIG. As shown in FIG. 7, in frequency converter 500A that performs frequency conversion from Ka band to K band, 2LO (19.6 GHz), which is a doubled LO signal, appears in the K band in-band.

[0032] (1-3) Frequency conversion from Ku band (receive) to Ku band (transmit) FIG. 8 is a diagram showing a schematic configuration example of a single-conversion frequency converter 500B according to the related art, which performs frequency conversion from the Ku band (reception) to the Ku band (transmission).

[0033] As shown in FIG. 8, the frequency converter 500B directly converts the uplink Ku-band (reception) RF signal into the downlink Ku-band (transmission) RF signal. Frequency converter 500B differs from frequency converter 500 in that LO502 is replaced with LO502B. LO502B generates an LO signal with an LO frequency of 2.05 GHz.

[0034] FIG. 9 is a diagram schematically illustrating an example of harmonic components of the LO signal in frequency converter 500B shown in FIG. As shown in FIG. 9, in a frequency converter 500B that performs frequency conversion from the Ku band (reception) to the Ku band (transmission), a six-times LO signal, 6LO (12.3 GHz), appears in the usable band (in-band) of the Ku band z (transmission).

[0035] As described above, the single-conversion frequency converters 500, 500A, and 500B according to the related art have a problem in that harmonic components of the LO signal appear as spurious components in the operating band (in-band).

[0036] Therefore, in recent years, in order to solve the above-mentioned problems with the single-conversion frequency converters 500, 500A, and 500B according to the related art, double-conversion frequency converters that convert an RF signal in the uplink frequency band into an RF signal in the downlink frequency band via an IF band have become mainstream. Next, a double-conversion frequency converter according to the related art and its problems will be described below.

[0037] (2) Related Technology Issue 2 (2-1) Frequency conversion from V band to Q band FIG. 10 is a diagram showing a schematic configuration example of a double-conversion frequency converter 600 according to the related art, which performs frequency conversion from V-band to Q-band.

[0038] As shown in FIG. 10, the frequency converter 600 converts the frequency of an uplink V-band RF signal into a downlink Q-band RF signal via an IF band. In a double-conversion frequency converter, a band lower than the uplink frequency band and the downlink frequency band is generally used as the IF band. Therefore, the frequency converter 600 uses the K band of 19.3 GHz to 24.5 GHz as the IF band.

[0039] The frequency converter 600 includes an LNA 601 , an LO 602 , a mixer 603 , a BPF (Band Pass Filter) 604 , an AMP (Amplifier) ​​605 , an LO 606 , a mixer 607 , and an MPA 608 .

[0040] The LNA 601 amplifies the RF signal input from the receiving antenna 11 and outputs the amplified signal. The LO 602 generates an LO1 signal with an LO frequency of 27.9 GHz. The mixer 603 receives the RF signal output from the LNA 601 and the LO1 signal generated by the LO 602, and outputs an RF signal in a frequency band that is the difference frequency between the two signals. In this way, the LO 602 and the mixer 603 frequency convert (down-convert) the RF signal from the V band to the K band. Hereinafter, this frequency conversion will be referred to as a first frequency conversion as appropriate. The BPF 604 suppresses RF signals outside the K band from among the RF signals output from the mixer 603 . The AMP 605 amplifies and outputs the RF signal output from the BPF 604. Note that the AMP 605 can be realized by, for example, an MPA, but is not limited to this. The LO 606 generates an LO2 signal with an LO frequency of 18.2 GHz. The mixer 607 receives the RF signal output from the AMP 605 and the LO2 signal generated by the LO 606, and outputs an RF signal in a frequency band that is the sum frequency of both signals. In this way, the LO 606 and the mixer 607 frequency convert (up-convert) the RF signal from the K band to the Q band. Hereinafter, this frequency conversion will be referred to as a second frequency conversion as appropriate. The MPA 608 amplifies the RF signal output from the mixer 607 and outputs it to the intra-satellite equipment 13 .

[0041] However, the frequency converter 600 uses the K band, which is lower than the V band and the Q band, as the IF band. Therefore, in frequency converter 600, the wavelength of the RF signal becomes longer, so that devices such as BPF 604 and AMP 605 become larger, and the circuit size of the connection circuit between mixer 603 and mixer 607, which is made up of a microstrip line and the like, becomes larger.

[0042] Furthermore, in frequency converter 600, the fractional bandwidth of the V band is 10%, while the fractional bandwidth of the K band, which is the IF band, is 21%. Therefore, it is difficult to ensure a wide bandwidth because the 5.2 GHz bandwidth of the V band cannot be ensured.

[0043] Fig. 11 is a diagram schematically showing an example of harmonic components of the LO1 signal and the LO2 signal in the frequency converter 600 shown in Fig. 10. Fig. 11 shows the harmonic components of the LO1 signal during the first frequency conversion, and also shows the harmonic components of the LO2 signal during the second frequency conversion. In Fig. 11, the horizontal axis represents frequency (the same applies to Figs. 13, 15, 17, 19, and 21 below).

[0044] As shown in Fig. 11, in the first frequency conversion from the V band to the K band, the LO frequency of the LO1 signal is 27.9 GHz. Here, the 1x LO1 signal (1LO1) is closest to the K band usage band (in-band), and 1LO1 (27.9 GHz) is 3.4 GHz away from 24.5 GHz, the upper limit of the K band usage band (in-band). However, in general, in nxLO (n = 1, 2, 3, ...), the signal strength decreases as n increases, and therefore 1LO1 has a high signal strength. Therefore, in order to suppress the 1LO1 signal with a high signal strength using BPF 604, the size of BPF 604 will inevitably become large.

[0045] Furthermore, in the second frequency conversion from K band to Q band, the LO frequency of the LO2 signal is 18.2 GHz. Here, the signal closest to the Q band's in-band is the doubled LO2 signal (2LO2), and 2LO2 (36.4 GHz) is only 0.8 GHz away from the lower limit of the Q band's in-band, 37.2 GHz. In other words, even if 2LO2 can be avoided outside the Q band's in-band, 2LO2 still appears near the in-band. Suppressing this 2LO1 signal using a filter inevitably requires a larger filter size.

[0046] (2-2) Frequency conversion from Ka band to K band FIG. 12 is a diagram showing a schematic configuration example of a double-conversion frequency converter 600A according to the related art, which performs frequency conversion from Ka band to K band.

[0047] As shown in FIG. 12, frequency converter 600A converts an uplink Ka-band RF signal into a downlink K-band RF signal via an IF band, using the Ku band of 10.0 GHz to 14.0 GHz as the IF band.

[0048] Frequency converter 600A differs from frequency converter 600 in that LO602 is replaced with LO602A and LO606 is replaced with LO606A. LO602A generates an LO1 signal with an LO frequency of 17.0 GHz. LO602A generates an LO2 signal with an LO frequency of 7.2 GHz.

[0049] FIG. 13 is a diagram schematically illustrating an example of harmonic components of the LO1 signal and the LO2 signal in the frequency converter 600A shown in FIG. As shown in Figure 13, in the first frequency conversion from the Ka band to the Ku band, the LO1 signal (17.0 GHz) with high signal strength and 1x the power appears at a position 3.0 GHz away from 14.0 GHz, which is the upper limit of the usable band (in-band) of the Ku band.

[0050] Furthermore, in the second frequency conversion from the Ku band to the K band, the tripled LO2 signal, 3LO2 (21.6 GHz), appears near the K band's in-band, i.e., only 0.4 GHz away from the upper limit of the in-band, 21.2 GHz.

[0051] (2-3) Frequency conversion from Ku band (receive) to Ku band (transmit) FIG. 14 is a diagram showing a schematic configuration example of a double-conversion frequency converter 600B according to the related art, which performs frequency conversion from the Ku band (reception) to the Ku band (transmission).

[0052] As shown in FIG. 14, frequency converter 600B converts an uplink Ku-band (receive) RF signal into a downlink Ku-band (transmit) RF signal via an IF band, and uses the C-band range of 3.75 GHz to 5.8 GHz as the IF band.

[0053] Frequency converter 600B differs from frequency converter 600 in that LO602 is replaced with LO602B and LO606 is replaced with LO606B. LO602B generates the LO1 signal with an LO frequency of 9.0 GHz. LO602B generates the LO2 signal with an LO frequency of 6.95 GHz.

[0054] FIG. 15 is a diagram schematically illustrating an example of harmonic components of the LO1 signal and the LO2 signal in the frequency converter 600B shown in FIG. As shown in Figure 15, in the first frequency conversion from the Ku band (reception) to the C band, the LO1 signal (9.0 GHz) with high signal strength and 1x the power appears at a position 3.2 GHz away from 5.8 GHz, which is the upper limit of the C band's usable band (in-band).

[0055] Furthermore, in the second frequency conversion from the C band to the Ku band (transmission), the 2LO2 (13.9 GHz) signal, which is twice the LO2 signal with a higher signal strength, appears near the in-band used in the Ku band (transmission), i.e., only 1.15 GHz away from the upper limit of the in-band, 12.75 GHz.

[0056] As described above, the double-conversion frequency converters 600, 600A, and 600B according to the related art use an IF band that is lower than the uplink and downlink frequency bands. This results in a problem of larger device and circuit sizes due to the longer wavelength of the RF signal. Another problem is that it is difficult to ensure a wide bandwidth.

[0057] Furthermore, in the double-conversion frequency converters 600, 600A, and 600B according to the related art, even if the harmonic components of the LO1 signal or the LO2 signal can be avoided outside the operating band (in-band), there is a problem in that harmonic components with high signal strength still appear near the in-band.

[0058] Each embodiment of the present disclosure described below solves at least one of the above-mentioned problems of double-conversion frequency converters 600, 600A, and 600B according to the related art.

[0059] <Embodiment 1 (V-band to Q-band frequency conversion)> FIG. 16 is a diagram illustrating a schematic configuration example of a double-conversion frequency converter 100 according to the present disclosure, which performs frequency conversion from V-band to Q-band.

[0060] As shown in FIG. 16, the frequency converter 100 converts an uplink V-band RF signal into a downlink Q-band RF signal via an IF band. Here, the frequency converter 100 uses the E band, 69.0 GHz to 74.2 GHz, as the IF band. Note that the IEEE (Institute of Electrical and Electronics Engineers) frequency band definition defines up to 75 GHz as the V band. However, in this specification, the above IF band is referred to as the E band to distinguish it from the uplink band (47.2 GHz to 52.4 GHz). The E band is not strictly defined and refers to the 70 GHz to 80 GHz band.

[0061] The frequency converter 100 includes an LNA 101, an LO 102, a mixer 103, a BPF 104, an AMP 105, an LO 106, a mixer 107, and an MPA 108. Of these, the LNA 101, the mixer 103, the BPF 104, the AMP 105, the mixer 107, and the MPA 108 are similar to the LNA 601, the mixer 603, the BPF 604, the AMP 605, the mixer 607, and the MPA 608, respectively.

[0062] On the other hand, the LO 102 generates an LO 1 signal with an LO frequency of 21.8 GHz. Therefore, the LO 102 and the mixer 103 frequency convert (up-convert) the RF signal from the V band to the E band. Hereinafter, this frequency conversion will be referred to as a first frequency conversion as appropriate.

[0063] The LO 106 generates an LO2 signal with an LO frequency of 31.5 GHz. Therefore, the LO 106 and the mixer 107 frequency convert (down-convert) the RF signal from the E band to the Q band. Hereinafter, this frequency conversion will be referred to as a second frequency conversion as appropriate.

[0064] In this way, the frequency converter 100 uses the E band, which is higher than the V band and the Q band, as the IF band. Therefore, in frequency converter 100, the wavelength of the RF signal is shortened, which allows devices such as BPF 104 and AMP 105 to be made smaller, and the circuit size of the connection circuit between mixer 103 and mixer 107, which consists of a microstrip line or the like, can be reduced.

[0065] Furthermore, in frequency converter 100, the center frequency of E-band, which is the IF band, is 71.6 GHz. Therefore, if 10% of the V-band bandwidth is applied to E-band, a bandwidth of about 7 GHz can be secured. Therefore, a wider bandwidth can be secured compared to when K-band is used as the IF band, as in frequency converter 600 according to the related art.

[0066] FIG. 17 is a diagram schematically illustrating an example of harmonic components of the LO1 signal and the LO2 signal in the frequency converter 100 shown in FIG. 17, in the first frequency conversion from the V band to the E band, the LO frequency of the LO1 signal is 21.8 GHz. Here, the LO frequency closest to the E band usage band (in-band) is the tripled LO1 signal (3LO1). 3LO1 (65.4 GHz) has a lower signal strength than 1LO1 and is 3.6 GHz away from 69.0 GHz, the lower limit of the E band usage band (in-band). Therefore, this 3LO1 can be suppressed by the BPF 104 without increasing the size of the BPF 104.

[0067] Furthermore, in the second frequency conversion from E-band to Q-band, the LO frequency of the LO2 signal is 31.5 GHz. Here, the 1x LO2 signal (1LO2) is closest to the Q-band in-band. Although the signal strength of 1LO2 (31.5 GHz) is high, it is sufficiently far from the lower limit of 37.2 GHz of the Q-band in-band by 5.7 GHz. Therefore, this 1LO2 can be suppressed by a filter equivalent to BPF 104.

[0068] In this way, in the frequency converter 100, in the first frequency conversion and the second frequency conversion, it is possible to prevent harmonic components with high signal strength of the LO1 signal or the LO2 signal from appearing as spurious components near the used band (In-band).

[0069] As described above, according to the first embodiment, the frequency converter 100 converts an uplink V-band RF signal into a downlink Q-band RF signal via an IF band, and uses the E-band (69.0 GHz-74.2 GHz) as the IF band.

[0070] In this way, the E band, which is higher than the V and Q bands, is used as the IF band, and the RF signal wavelength is shortened, which allows for the miniaturization of devices and circuits. In addition, the use of the high E band as the IF band ensures a wide bandwidth.

[0071] Furthermore, it is possible to prevent harmonic components with high signal strength of the LO1 signal or the LO2 signal from appearing as spurious signals near the in-band.

[0072] <Embodiment 2 (Frequency conversion from Ka band to K band)> FIG. 18 is a diagram illustrating a schematic configuration example of a double-conversion frequency converter 100A according to the present disclosure, which performs frequency conversion from Ka band to K band.

[0073] As shown in FIG. 18, frequency converter 100A converts an uplink Ka-band RF signal into a downlink K-band RF signal via an IF band, using the V band of 51.0 GHz-55.0 GHz as the IF band.

[0074] Frequency converter 100A differs from frequency converter 100 in that LO 102 is replaced with LO 102A and LO 106 is replaced with LO 106A. The LO 102A generates an LO1 signal with an LO frequency of 24.0 GHz. The LO 102A generates an LO2 signal with an LO frequency of 33.8 GHz.

[0075] FIG. 19 is a diagram schematically illustrating an example of harmonic components of the LO1 signal and the LO2 signal in the frequency converter 100A shown in FIG. 19, in the first frequency conversion from Ka band to V band, the signal closest to the V band's in-band is the doubled LO1 signal (2LO1). 2LO1 (48.0 GHz) has lower signal strength than 1LO1, and is 3.0 GHz away from 51.0 GHz, the lower limit of the V band's in-band.

[0076] In the second frequency conversion from the V band to the K band, the signal closest to the in-band of the K band is the 1x LO2 signal (1LO2). Although the signal strength of 1LO2 (33.8 GHz) is high, it is 12.6 GHz away from the upper limit of the in-band of the K band (21.2 GHz).

[0077] As described above, according to the second embodiment, the frequency converter 100A converts an uplink Ka-band RF signal into a downlink K-band RF signal via an IF band, and uses the V-band range of 51.0 GHz to 55.0 GHz as the IF band.

[0078] In this way, the V band, which is higher than the Ka and K bands, is used as the IF band, and the shorter wavelengths allow for the miniaturization of devices and circuits. In addition, the use of the high V band as the IF band ensures a wide bandwidth.

[0079] Furthermore, it is possible to prevent harmonic components with high signal strength of the LO1 signal or the LO2 signal from appearing as spurious signals near the in-band.

[0080] <Embodiment 3 (Frequency conversion from Ku band (reception) to Ku band (transmission))> FIG. 20 is a diagram illustrating a schematic configuration example of a double-conversion frequency converter 100B according to the present disclosure, which performs frequency conversion from the Ku band (reception) to the Ku band (transmission).

[0081] As shown in FIG. 20, the frequency converter 100B converts an uplink Ku-band (receive) RF signal into a downlink Ku-band (transmit) RF signal via an IF band, using the Ka-band 29.75 GHz-31.8 GHz as the IF band.

[0082] Frequency converter 100A differs from frequency converter 100 in that LO 102 is replaced with LO 102B and LO 106 is replaced with LO 106B. The LO102B generates an LO1 signal with an LO frequency of 17.0 GHz. LO102B generates the LO2 signal with an LO frequency of 19.05 GHz.

[0083] FIG. 21 is a diagram schematically illustrating an example of harmonic components of the LO1 signal and the LO2 signal in the frequency converter 100B shown in FIG. 21, in the first frequency conversion from the Ku band (reception) to the Ka band, the 1x LO1 signal (1LO1) is closest to the Ka band usage band (in-band). Although the signal strength of 1LO1 (17.0 GHz) is high, it is far enough, at 12.75 GHz, from the lower limit of the Ka band usage band (in-band), which is 29.75 GHz.

[0084] In the second frequency conversion from the Ka band to the Ku band (transmission), the signal closest to the in-band of the Ku band (transmission) is the 1x LO2 signal (1LO2). Although the signal strength of 1LO2 (19.05 GHz) is high, it is far enough away from the upper limit of the in-band of the Ku band (transmission), 12.75 GHz, by 6.3 GHz.

[0085] As described above, according to the third embodiment, the frequency converter 100B converts an uplink Ku-band (receive) RF signal into a downlink Ku-band (transmit) RF signal via an IF band, and uses the Ka band of 29.75 GHz to 31.8 GHz as the IF band.

[0086] In this way, the Ka band, which is higher than the Ku band (receive) and Ku band (transmit), is used as the IF band, and the wavelength of the RF signal is shortened, which allows for the miniaturization of devices and circuits.In addition, the use of the high Ka band as the IF band ensures a wide bandwidth.

[0087] Furthermore, it is possible to prevent harmonic components with high signal strength of the LO1 signal or the LO2 signal from appearing as spurious signals near the in-band.

[0088] <Fourth Embodiment> The fourth embodiment corresponds to an embodiment that is a superordinate concept of the first to third embodiments described above. FIG. 22 is a diagram illustrating a schematic configuration example of a double-conversion frequency converter 100C according to the present disclosure. As shown in FIG. 22, the frequency converter 100C includes a first frequency converter 110 and a second frequency converter 120.

[0089] The first frequency converter 110 frequency-converts the RF signal in the first frequency band into an RF signal in the intermediate frequency band. The second frequency converter 120 frequency converts the RF signal in the intermediate frequency band into an RF signal in the second frequency band. Here, the intermediate frequency band is higher than the first frequency band and the second frequency band.

[0090] As described above, according to the fourth embodiment, a frequency band higher than the first and second frequency bands is used as the intermediate frequency band, which makes it possible to reduce the size of devices and circuits and ensure a wide bandwidth.

[0091] When the first frequency band is the V band and the second frequency band is the Q band, the intermediate frequency band may be the E band, which is higher than the V band and the Q band. More specifically, when the first frequency band is the V band, which is 47.2 GHz to 52.4 GHz, and the second frequency band is the Q band, which is 37.5 GHz to 42.7 GHz, the intermediate frequency band may be the E band, which is 69.0 GHz to 74.2 GHz.

[0092] Furthermore, when the first frequency band is the Ka band and the second frequency band is the K band, the intermediate frequency band may be the V band, which is higher than the Ka band and the K band. More specifically, when the first frequency band is the Ka band, 27.0 GHz-31.0 GHz, and the second frequency band is the K band, 17.2 GHz-21.2 GHz, the intermediate frequency band may be the V band, 51.0 GHz-55.0 GHz.

[0093] Furthermore, when the first frequency band is the first band of the Ku band and the second frequency band is the second band of the Ku band, the intermediate frequency band may be the Ka band, which is higher than the first and second bands of the Ku band. More specifically, when the first frequency band is 12.75 GHz-14.8 GHz, which is the first band of the Ku band, and the second frequency band is 10.7 GHz-12.75 GHz, which is the second band of the Ku band, the intermediate frequency band may be 29.75 GHz-31.8 GHz in the Ka band.

[0094] The first frequency conversion section 110 may also include a first local oscillator and a first mixer. In this case, the first local oscillator may generate a first local oscillation signal of a first local oscillation frequency. The first mixer may also receive an RF signal in a first frequency band and the first local oscillation signal, and output an RF signal in a frequency band that is the difference between the first frequency band and the first local oscillation frequency as an RF signal in an intermediate frequency band.

[0095] The second frequency conversion section 120 may also include a second local oscillator and a second mixer. In this case, the second local oscillator may generate a second local oscillation signal of a second local oscillation frequency. The second mixer may also receive an RF signal in an intermediate frequency band and the second local oscillation signal, and output an RF signal in a frequency band that is the sum of the intermediate frequency band and the second local oscillation frequency as an RF signal in the second frequency band. The frequency converter 100C may also be mounted on an artificial satellite.

[0096] <Hardware configuration of frequency converter> FIG. 23 is a diagram illustrating an example of a schematic hardware configuration of a computer 900 that implements some or all of the functions of the frequency converters 100, 100A, 100B, and 100C described above. 23, a computer 900 includes a processor 901 and a memory 902. The processor 901 and the memory 902 are coupled to each other.

[0097] The processor 901 may be, for example, a microprocessor, a microprocessing unit (MPU), or a central processing unit (CPU). The processor 901 may include multiple processors.

[0098] The memory 902 is configured by a combination of volatile memory and non-volatile memory. The memory 902 may include storage located remotely from the processor 901. In this case, the processor 901 may access the memory 902 via an I (Input) / O (Output) interface (not shown).

[0099] The memory 902 may store software modules (computer programs) including instructions and data for performing processing by the frequency converters 100, 100A, 100B, and 100C described above.

[0100] In some implementations, the processor 901 may be configured to read and execute software modules from the memory 902 to perform the processing of the frequency converters 100, 100A, 100B, and 100C described above.

[0101] The above-described programs may also be stored on non-transitory computer-readable media or tangible storage media. By way of example and not limitation, computer-readable media or tangible storage media include random access memory (RAM), read-only memory (ROM), flash memory, solid-state drives (SSD) or other memory technologies, compact discs (CD)-ROMs, digital versatile discs (DVDs), Blu-ray discs or other optical disc storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices. The programs may also be transmitted on transitory computer-readable media or communication media. By way of example and not limitation, transitory computer-readable media or communication media include electrical, optical, acoustic, or other forms of propagated signals.

[0102] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0103] Furthermore, each drawing is merely an example for describing one or more embodiments. Each drawing may relate not only to one particular embodiment, but also to one or more other embodiments. As will be understood by those skilled in the art, various features or steps described with reference to any one drawing can be combined with features or steps shown in one or more other drawings to create, for example, an embodiment not explicitly shown or described. Not all features or steps shown in any one drawing are necessarily required to describe an exemplary embodiment, and some features or steps may be omitted. The order of steps described in any drawing may be changed as appropriate.

[0104] Furthermore, some or all of the above-described embodiments can be described as, but are not limited to, the following supplementary notes. (Appendix 1) A double-conversion frequency converter, a first frequency conversion unit that converts a radio frequency (RF) signal in a first frequency band into an RF signal in an intermediate frequency band; a second frequency conversion unit that converts the RF signal in the intermediate frequency band into an RF signal in a second frequency band, the intermediate frequency band is higher than the first frequency band and the second frequency band; Frequency converter. (Appendix 2) When the first frequency band is a V band and the second frequency band is a Q band, the intermediate frequency band is an E band, which is higher than the V band and the Q band. 10. A frequency converter as defined in claim 1. (Appendix 3) When the first frequency band is 47.2 GHz-52.4 GHz in the V band and the second frequency band is 37.5 GHz-42.7 GHz in the Q band, the intermediate frequency band is 69.0 GHz-74.2 GHz in the E band; 10. A frequency converter as defined in claim 2. (Appendix 4) When the first frequency band is the Ka band and the second frequency band is the K band, the intermediate frequency band is the V band, which is higher than the Ka band and the K band. 10. A frequency converter as defined in claim 1. (Appendix 5) When the first frequency band is 27.0 GHz-31.0 GHz in the Ka band and the second frequency band is 17.2 GHz-21.2 GHz in the K band, the intermediate frequency band is 51.0 GHz-55.0 in the V band; 5. A frequency converter as defined in claim 4. (Appendix 6) When the first frequency band is a first band of the Ku band and the second frequency band is a second band of the Ku band, the intermediate frequency band is a Ka band, which is higher than the first band and the second band of the Ku band. 10. A frequency converter as defined in claim 1. (Appendix 7) When the first frequency band is 12.75 GHz to 14.8 GHz, which is the first band of the Ku band, and the second frequency band is 10.7 GHz to 12.75 GHz, which is the second band of the Ku band, the intermediate frequency band is 29.75 GHz to 31.8 GHz, which is the Ka band. 7. A frequency converter as defined in claim 6. (Appendix 8) The first frequency conversion unit a first local oscillator that generates a first local oscillation signal at a first local oscillation frequency; a first mixer that receives an RF signal in the first frequency band and the first local oscillation signal, and outputs an RF signal in a frequency band that is a difference between the first frequency band and the first local oscillation frequency, as an RF signal in the intermediate frequency band; The second frequency conversion unit a second local oscillator that generates a second local oscillation signal at a second local oscillation frequency; a second mixer that receives the RF signal of the intermediate frequency band and the second local oscillation signal and outputs the RF signal of the frequency band that is the sum of the intermediate frequency band and the second local oscillation frequency as the RF signal of the second frequency band, 10. A frequency converter as defined in claim 1. (Appendix 9) The frequency converter is mounted on a satellite. 10. A frequency converter as defined in claim 1. (Appendix 10) A frequency conversion method performed by a double-conversion frequency converter, comprising: frequency converting a radio frequency (RF) signal in a first frequency band into an RF signal in an intermediate frequency band; frequency converting the RF signal in the intermediate frequency band into an RF signal in a second frequency band; the intermediate frequency band is higher than the first frequency band and the second frequency band; Frequency conversion method.

[0105] Note that some or all of the elements (e.g., configurations and functions) described in Supplementary Notes 2 to 9 that are dependent on Supplementary Note 1 may also be dependent on Supplementary Note 10 in the same dependent relationship as Supplementary Notes 2 to 9. Some or all of the elements described in any Supplementary Note may be applied to various hardware, software, recording means for recording software, systems, and methods. [Explanation of symbols]

[0106] 10 satellite 11 Receiving antenna 12 Frequency converter 13 Satellite equipment 14 transmitting antenna 20X,20Y ground station 100, 100A, 100B, 100C frequency converter 101 LNA 102, 102A, 102B LO 103 Mixer 104 BPF 105 AMP 106, 106A, 106B LO 107 Mixer 108 MPA 110 First frequency conversion unit 120 Second frequency conversion unit 900 Computers 901 processor 902 memory

Claims

1. A double-conversion frequency converter, a first frequency conversion unit that converts a radio frequency (RF) signal in a first frequency band into an RF signal in an intermediate frequency band; a second frequency conversion unit that converts the RF signal in the intermediate frequency band into an RF signal in a second frequency band, the intermediate frequency band is higher than the first frequency band and the second frequency band; Frequency converter.

2. When the first frequency band is a V band and the second frequency band is a Q band, the intermediate frequency band is an E band which is higher than the V band and the Q band.

2. The frequency converter according to claim 1.

3. When the first frequency band is 47.2 GHz to 52.4 GHz in the V band and the second frequency band is 37.5 GHz to 42.7 GHz in the Q band, the intermediate frequency band is 69.0 GHz to 74.2 GHz in the E band.

3. The frequency converter according to claim 2.

4. When the first frequency band is the Ka band and the second frequency band is the K band, the intermediate frequency band is the V band, which is higher than the Ka band and the K band.

2. The frequency converter according to claim 1.

5. When the first frequency band is 27.0 GHz to 31.0 GHz in the Ka band and the second frequency band is 17.2 GHz to 21.2 GHz in the K band, the intermediate frequency band is 51.0 GHz to 55.0 GHz in the V band.

5. The frequency converter according to claim 4.

6. When the first frequency band is a first band of the Ku band and the second frequency band is a second band of the Ku band, the intermediate frequency band is a Ka band which is higher than the first band and the second band of the Ku band.

2. The frequency converter according to claim 1.

7. When the first frequency band is 12.75 GHz to 14.8 GHz, which is the first band of the Ku band, and the second frequency band is 10.7 GHz to 12.75 GHz, which is the second band of the Ku band, the intermediate frequency band is 29.75 GHz to 31.8 GHz, which is the Ka band.

7. The frequency converter according to claim 6.

8. The first frequency conversion unit a first local oscillator for generating a first local oscillation signal at a first local oscillation frequency; a first mixer that receives an RF signal in the first frequency band and the first local oscillation signal, and outputs an RF signal in a frequency band that is a difference between the first frequency band and the first local oscillation frequency, as an RF signal in the intermediate frequency band; The second frequency conversion unit a second local oscillator for generating a second local oscillation signal at a second local oscillation frequency; a second mixer that receives the RF signal of the intermediate frequency band and the second local oscillation signal and outputs an RF signal of a frequency band that is the sum of the intermediate frequency band and the second local oscillation frequency as an RF signal of the second frequency band, 2. The frequency converter according to claim 1.

9. The frequency converter is mounted on a satellite.

2. The frequency converter according to claim 1.

10. A frequency conversion method performed by a double-conversion frequency converter, comprising: frequency converting a radio frequency (RF) signal in a first frequency band into an RF signal in an intermediate frequency band; frequency converting the RF signal in the intermediate frequency band into an RF signal in a second frequency band; the intermediate frequency band is higher than the first frequency band and the second frequency band; Frequency conversion method.

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