Antenna module and communication device comprising same

Abstract

An antenna module (100) comprises a flat plate–shaped radiation element (121), a ground electrode (GND) that is provided opposite the radiation element (121), power supply wiring (141, 142), and stubs (ST1, ST2) that function as band-stop filters. The power supply wiring (141) transmits a high-frequency signal in a first frequency band to a power supply point (SP1) on the radiation element. The power supply wiring (142) transmits a high-frequency signal in a second frequency band that is higher than the first frequency band to a power supply point (SP2) on the radiation element. The stub (ST1) is connected to the power supply wiring (141) and is configured to prevent passage of the high-frequency signal in the second frequency band. The stub (ST2) is connected to the power supply wiring (142) and is configured to prevent passage of the high-frequency signal in the first frequency band.

Description

Antenna module and communication device equipped with same

[0001] The present disclosure relates to an antenna module and a communication device including the same, and more particularly to a technique for radiating radio waves in multiple frequency bands using a single radiating element.

[0002] International Publication No. 2023 / 100621 (Patent Document 1) discloses a so-called dual-band type antenna module that uses two different radiating elements stacked on a dielectric substrate to radiate radio waves in two frequency bands.

[0003] WO 2023 / 100621

[0004] In the antenna module disclosed in WO 2023 / 100621 (Patent Document 1), two radiating elements are arranged so as to overlap when viewed in a plan view from the normal direction of the dielectric substrate. In such a configuration, it is preferable to arrange the radiating elements so that their centers coincide with each other, but if the positions of the two radiating elements are misaligned due to variations during manufacturing, etc., this can be a factor in degrading the antenna characteristics.

[0005] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to provide an antenna module that is capable of radiating radio waves in multiple frequency bands using a single radiating element.

[0006] The antenna module according to the present disclosure includes a flat radiating element, a ground electrode disposed opposite the radiating element, first and second feed lines, and first and second band-stop filters. The first feed line transmits high-frequency signals in a first frequency band to a first feed point of the radiating element. The second feed line transmits high-frequency signals in a second frequency band higher than the first frequency band to a second feed point of the radiating element. The first band-stop filter is connected to the first feed line and configured to block passage of high-frequency signals in the second frequency band. The second band-stop filter is connected to the second feed line and configured to block passage of high-frequency signals in the first frequency band.

[0007] In the antenna module according to the present disclosure, high-frequency signals in different frequency bands are transmitted to a common radiating element via two power feed lines (first power feed line and second power feed line). Furthermore, each power feed line is provided with a band-stop filter configured to block the passage of high-frequency signals transmitted by the other power feed line. This configuration makes it possible to radiate radio waves in multiple frequency bands using a single radiating element while suppressing degradation of antenna characteristics.

[0008] 1 is an overall configuration diagram of a communication device equipped with an antenna module according to embodiment 1. FIG. 2 is a plan view of the antenna module according to embodiment 1. FIG. 3 is a side perspective view of the antenna module of FIG. 2. FIG. 4 is a diagram showing antenna characteristics when viewed from each power supply wiring in the antenna module of FIG. 2. FIG. 5 is a plan view of the antenna module of modified example 1. FIG. 6 is a plan view of the antenna module of modified example 2. FIG. 7 is a plan view of the antenna module of modified example 3. FIG. 8 is a plan view of the antenna module of modified example 4. FIG. 9 is a plan view of the antenna module of modified example 5. FIG. 10 is a plan view of the antenna module according to embodiment 2. FIG. 11 is a plan view of the antenna module of modified example 1. FIG. 12 is a side perspective view of the antenna module of modified example 1. FIG. 13 is a plan view of the antenna module of modified example 1.

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0010] [First Embodiment] (Basic Configuration of Communication Device) Fig. 1 is a block diagram of a communication device 10 to which an antenna module 100 according to this embodiment is applied. The communication device 10 is, for example, a mobile terminal such as a mobile phone, smartphone, or tablet, or a personal computer with a communication function. An example of the frequency band of radio waves used in the antenna module 100 according to this embodiment is millimeter-wave radio waves with center frequencies of 28 GHz and 39 GHz, for example, but radio waves in other frequency bands are also applicable.

[0011] 1, a communication device 10 includes an antenna module 100 and a BBIC 200 that configures a baseband signal processing circuit. The antenna module 100 includes an RFIC 110, which is an example of a power supply circuit, and an antenna device 120.

[0012] The communication device 10 upconverts the signal transmitted from the BBIC 200 to the antenna module 100 into a high-frequency signal and radiates it from the antenna device 120, and downconverts the high-frequency signal received by the antenna device 120 and processes the signal in the BBIC 200.

[0013] The antenna device 120 includes a dielectric substrate 130 and a plurality of radiating elements arranged on the dielectric substrate 130. While Fig. 1 shows an example in which four radiating elements 121 are arranged on the dielectric substrate 130, the number of radiating elements arranged on the dielectric substrate 130 is not limited to this. A single radiating element 121 may be arranged on the dielectric substrate 130, or a plurality of radiating elements may be arranged on the dielectric substrate 130. Furthermore, Fig. 1 shows an example in which the radiating elements 121 are arranged in a one-dimensional array on the dielectric substrate 130, in which they are arranged in a line, but the radiating elements may also be arranged in a two-dimensional array on the dielectric substrate 130.

[0014] In the first embodiment, the radiating element 121 is a microstrip antenna having a substantially square flat plate shape. The shape of the radiating element 121 may be a circle, an ellipse, or another polygon.

[0015] Each of the radiating elements 121 has two feed points SP1 and SP2, and a high-frequency signal is individually supplied to each feed point from the RFIC 110. As will be described later, in the antenna module 100 of the first embodiment, high-frequency signals of two different frequency bands are supplied to one radiating element 121. In each radiating element 121, a high-frequency signal of a first frequency band on the low frequency side is supplied to the feed point SP1, and a high-frequency signal of a second frequency band on the high frequency side is supplied to the feed point SP2. In the example of the first embodiment, the first frequency band is the 28 GHz band (24.25 GHz to 29.5 GHz), and the second frequency band is the 39 GHz band (37 GHz to 43.5 GHz).

[0016] The RFIC 110 includes switches 111A to 111H, 113A to 113H, 117A, and 117B, power amplifiers 112AT to 112HT, low-noise amplifiers 112AR to 112HR, attenuators 114A to 114H, phase shifters 115A to 115H, signal combiners / dividers 116A and 116B, mixers 118A and 118B, and amplifier circuits 119A and 119B. Of these, the configuration of switches 111A to 111D, 113A to 113D, and 117A, power amplifiers 112AT to 112DT, low-noise amplifiers 112AR to 112DR, attenuators 114A to 114D, phase shifters 115A to 115D, signal combiner / divider 116A, mixer 118A, and amplifier circuit 119A constitutes a circuit for high-frequency signals in the first frequency band. Also, the configuration of switches 111E to 111H, 113E to 113H, and 117B, power amplifiers 112ET to 112HT, low-noise amplifiers 112ER to 112HR, attenuators 114E to 114H, phase shifters 115E to 115H, signal combiner / divider 116B, mixer 118B, and amplifier circuit 119B constitutes a circuit for high-frequency signals in the second frequency band.

[0017] When transmitting a high frequency signal, the switches 111A to 111H and 113A to 113H are switched to the power amplifiers 112AT to 112HT, and the switches 117A and 117B are connected to the transmission amplifiers of the amplifier circuits 119A and 119B. When receiving a high frequency signal, the switches 111A to 111H and 113A to 113H are switched to the low noise amplifiers 112AR to 112HR, and the switches 117A and 117B are connected to the reception amplifiers of the amplifier circuits 119A and 119B.

[0018] The signal transmitted from the BBIC 200 is amplified by amplifier circuits 119A and 119B and up-converted by mixers 118A and 118B. The up-converted high-frequency transmission signal is split into four by signal combiners / dividers 116A and 116B, passes through the corresponding signal paths, and is fed to the radiating elements. By individually adjusting the phase shift of phase shifters 115A to 115H arranged on each signal path, the directivity of the radio waves output from the radiating elements on each board can be adjusted. In addition, attenuators 114A to 114H adjust the strength of the transmission signal.

[0019] Terminals P1 to P4 of switches 111A to 111D are respectively connected to feed point SP1 of corresponding radiating element 121. Terminals P5 to P8 of switches 111E to 111H are respectively connected to feed point SP2 of corresponding radiating element 121.

[0020] The received signals, which are high-frequency signals received by the radiating element 121, are transmitted to the RFIC 110 and then combined in the signal combiners / dividers 116A and 116B via four different signal paths. The combined received signals are down-converted in the mixers 118A and 118B, and further amplified in the amplifier circuits 119A and 119B before being transmitted to the BBIC 200.

[0021] The RFIC 110 is formed as, for example, a one-chip integrated circuit component including the above circuit configuration. Alternatively, the devices (switches, power amplifiers, low-noise amplifiers, attenuators, phase shifters) corresponding to the respective radiating elements 121 in the RFIC 110 may be formed as one-chip integrated circuit components for each corresponding radiating element.

[0022] (Configuration of Antenna Module) Next, the configuration of the antenna module 100 according to the first embodiment will be described in detail with reference to Fig. 2 and Fig. 3. Fig. 2 is a plan view of the antenna module 100, and Fig. 3 is a side perspective view of the antenna module 100.

[0023] 2 and 3, the antenna module 100 includes, in addition to the radiating element 121 and the RFIC 110, a dielectric substrate 130, a ground electrode GND, and feed lines 141 and 142. Note that the dielectric of the dielectric substrate 130 is omitted in Fig. 2 and the subsequent plan views.

[0024] The dielectric substrate 130 has a substantially rectangular parallelepiped shape including two rectangular main surfaces 131, 132 facing each other. In the following description, the normal direction to the main surfaces 131, 132 of the dielectric substrate 130 is referred to as the Z-axis direction. The direction along one side of each of the main surfaces 131, 132 of the dielectric substrate 130 is referred to as the X-axis direction, and the direction along the other side is referred to as the Y-axis direction. In each drawing, the positive direction of the Z-axis may also be referred to as the upper side, and the negative direction may also be referred to as the lower side.

[0025] The dielectric substrate 130 may be, for example, a low temperature co-fired ceramics (LTCC) multilayer substrate, a multilayer resin substrate formed by laminating multiple resin layers made of resins such as epoxy or polyimide, a multilayer resin substrate formed by laminating multiple resin layers made of liquid crystal polymer (LCP) having a lower dielectric constant, a multilayer resin substrate formed by laminating multiple resin layers made of fluorine-based resin, a multilayer resin substrate formed by laminating multiple resin layers made of PET (Polyethylene Terephthalate), or a ceramic multilayer substrate other than LTCC. Note that the dielectric substrate 130 does not necessarily have a multilayer structure and may be a single-layer substrate.

[0026] The dielectric substrate 130 has a rectangular shape when viewed from above in the normal direction (Z-axis direction). The radiating element 121 is disposed at a position close to the main surface 131 on the upper surface side of the dielectric substrate 130. The radiating element 121 may be disposed in a manner that exposes it on the surface of the dielectric substrate 130, or may be disposed on an inner layer of the dielectric substrate 130 as in the example of FIG. 3 .

[0027] In the dielectric substrate 130, a ground electrode GND is arranged over the entire surface, closer to the main surface 132 than the radiating element 121, facing the radiating element 121. In addition, the RFIC 110 is mounted on the main surface 132 of the dielectric substrate 130 via solder bumps 160. Note that the RFIC 110 may be connected to the dielectric substrate 130 using a multi-pole connector instead of a solder connection.

[0028] When the radiating element 121 is viewed in a plan view from the Z-axis direction, a feed point SP1 is disposed at a position offset from the center of the radiating element 121 in the positive direction of the Y-axis, and a feed point SP2 is disposed at a position offset from the center of the radiating element 121 in the negative direction of the Y-axis. A high-frequency signal is supplied to the feed point SP1 from the RFIC 110 via a feed wiring 141. A high-frequency signal is supplied to the feed point SP2 from the RFIC 110 via a feed wiring 142. By supplying a high-frequency signal to each of the feed points SP1 and SP2, radio waves polarized in the Y-axis direction are radiated in the positive direction of the Z-axis.

[0029] 1, a high-frequency signal in a first frequency band on the relatively low frequency side is supplied to feed point SP1, and a high-frequency signal in a second frequency band on the relatively high frequency side is supplied to feed point SP2. In other words, antenna module 100 is a so-called dual-band antenna module that can radiate radio waves of two different frequencies using a single radiating element. Antenna module 100 can radiate radio waves of the two frequencies alternately or simultaneously.

[0030] 2 , the feed line 141 extends in the negative direction of the X axis from a position further in the positive direction of the X axis than the radiating element 121 toward the radiating element 121, rises from below the feed point SP1, and is connected to the feed point SP1. The feed line 142 extends in the positive direction of the X axis from a position further in the negative direction of the X axis than the radiating element 121 toward the radiating element 121, rises from below the feed point SP2, and is connected to the feed point SP2. By arranging the feed line 141 and the feed line 142 so that they extend in opposite directions relative to the radiating element 121, it is possible to suppress coupling between the feed line 141 and the feed line 142. This ensures isolation between the feed lines.

[0031] Linear stubs ST1 and ST2 are provided on the power supply lines 141 and 142, respectively. Each of the stubs ST1 and ST2 is an open stub with one end connected to the corresponding power supply line and the other end open. The stubs ST1 and ST2 function as band-stop filters that block the transmission of signals in the other's frequency band. Therefore, the line length of each of the stubs ST1 and ST2 is set to a quarter wavelength at the center frequency of the frequency band of the high-frequency signal supplied to the other's power supply line.

[0032] More specifically, the line length L1 of the stub ST1 is set to be equal to or longer than λ 1 , where λ 1 is the wavelength of the high-frequency signal in the second frequency band supplied to the feeder line 142. ２ (second wavelength), L1 = λ ２ Similarly, the line length L2 of the stub ST2 is set to λ / 4. １ (first wavelength), L2 = λ １ The shape of the stubs ST1 and ST2 may be a straight line as shown in Fig. 2, or may be a curved shape such as an L-shape.

[0033] Generally, the dimension of the radiating element 121 in the polarization direction is set to 1 / 2 of the wavelength corresponding to the center frequency of the high-frequency signal to be radiated. As described above, the antenna module 100 radiates radio waves in two frequency bands using the common radiating element 121, so it is preferable to set the resonant frequency of the radiating element 121 to be between the frequencies of the two radio waves. In other words, it is preferable to set the wavelength corresponding to the resonant frequency of the radiating element 121 to be longer than the wavelength of the radio wave on the higher frequency side and shorter than the wavelength of the radio wave on the lower frequency side.

[0034] Specifically, in the case of a substantially square radiating element 121, the length of one side of the radiating element 121 (i.e., the length along the polarization direction) Lp is set to satisfy L1 < Lp / 2 < L2. Furthermore, this relational expression can be expressed using the wavelength of the radio wave to be radiated as λ ２ / 2<Lp<λ １ / 2.

[0035] In practice, it is possible to radiate radio waves in two frequency bands from a single radiating element even when the frequencies of the two radio waves are both higher than the resonant frequency of the radiating element 121, or when the frequencies of the two radio waves are both lower. However, in this case, the antenna characteristics of the radio wave with the larger difference from the resonant frequency of the radiating element 121 may be lower than the other. For this reason, it is preferable to set the resonant frequency of the radiating element 121 to a frequency between the two frequency bands to be radiated.

[0036] Furthermore, the feed lines 141 and 142 may be provided with matching elements to adjust the impedance with the radiating element 121. In the example of Fig. 2, the feed line 141 is provided with a stub 151 that functions as a matching element, and the feed line 142 is provided with a stub 152 that also functions as a matching element. Note that the impedance with the radiating element 121 can also change depending on the connection positions of stubs ST1 and ST2 on the feed lines 141 and 142. Therefore, if the desired impedance can be achieved by the connection positions of stubs ST1 and ST2, there are cases where matching stubs 151 and 152 are not provided.

[0037] In the antenna module 100 configured as described above, when a low-frequency signal is supplied by the power feed line 141, the stub ST2, which functions as a band-stop filter, can prevent leakage of the high-frequency signal to the power feed line 142. Furthermore, when a high-frequency signal is supplied by the power feed line 142, the stub ST1 can prevent leakage of the signal to the power feed line 141. This makes it possible to radiate radio waves in two frequency bands using a common radiating element while ensuring isolation between the power feed lines 141 and 142.

[0038] Fig. 4 is a diagram showing the antenna characteristics of the antenna module of Fig. 2 as viewed from the power feed lines 141 and 142. In Fig. 4, the horizontal axis represents frequency, and the vertical axis represents insertion loss (solid lines LN10 and LN20) and reflection loss (dashed lines LN11 and LN21). The left diagram of Fig. 4 shows the antenna characteristics as viewed from the power feed line 141, and the right diagram of Fig. 4 shows the antenna characteristics as viewed from the power feed line 142.

[0039] 4, the feed line 141, through which the low-frequency signal is transmitted, has an attenuation pole near 39 GHz, and an attenuation of 10 dB or more can be ensured in the high-frequency band BP2. This prevents the high-frequency signal supplied to the feed line 142 from passing to the feed line 141. On the other hand, in the low-frequency band BP1, the insertion loss is 3 dB or less, and the high-frequency signal of the radio wave to be radiated can be transmitted to the radiating element 121 with little loss.

[0040] Similarly, for the feed line 142 through which the high-frequency signal on the high frequency side is transmitted, an attenuation pole occurs near 25 GHz, as shown in the right diagram of Figure 4, and an attenuation of 10 dB or more can be ensured in the frequency band BP1 on the low frequency side. This prevents the high-frequency signal supplied to the feed line 141 from passing to the feed line 142. On the other hand, in the frequency band BP2 on the high frequency side, the insertion loss is 3 dB or less, and the high-frequency signal of the radio wave to be radiated can be transmitted to the radiating element 121 with little loss.

[0041] Conventionally, dual-band antenna modules have been known in which two radiating elements corresponding to each frequency band are stacked in the normal direction of a dielectric substrate. However, in such a configuration, misalignment of the two radiating elements due to manufacturing variations can degrade the antenna characteristics.

[0042] However, it is possible to realize a dual-band antenna module in which degradation of antenna characteristics due to misalignment of the radiating element is suppressed by supplying high-frequency signals in two different frequency bands to a common radiating element, as in the antenna module 100 of embodiment 1. Furthermore, by providing a band-stop filter for each power feed line that blocks the passage of signals in the frequency band supplied to the other power feed line, isolation between the power feed lines 141 and 142 can be ensured and degradation of antenna characteristics due to signal leakage can be suppressed.

[0043] The "power supply wiring 141" and the "power supply wiring 142" in the first embodiment correspond to the "first power supply wiring" and the "second power supply wiring" in the present disclosure, respectively. The "stub ST1" and the "stub ST2" in the first embodiment correspond to the "first band-stop filter" and the "second band-stop filter" in the present disclosure, respectively. The "frequency band BP1" and the "frequency band BP2" in the first embodiment correspond to the "first frequency band" and the "second frequency band" in the present disclosure, respectively. The "stub 151" and the "stub 152" in the first embodiment each correspond to a "matching element" in the present disclosure.

[0044] (Modification 1) In Modification 1 and Modification 2 described later, different aspects of the band-stop filter will be described.

[0045] Fig. 5 is a plan view of an antenna module 100A according to Modification 1. In the antenna module 100A, the stubs ST1 and ST2 in the antenna module 100 of Fig. 2 are replaced with stubs ST1A and ST2A, respectively. The other configuration of the antenna module 100A is the same as that of the antenna module 100, and description of elements that overlap with those of the antenna module 100 will not be repeated.

[0046] 5, stubs ST1A and ST2A are short stubs with one end connected to the ground electrode GND. That is, one end of stub ST1A is connected to the power supply line 141, and the other end is connected to the ground electrode GND. Similarly, one end of stub ST2A is connected to the power supply line 142, and the other end is connected to the ground electrode GND.

[0047] The stubs ST1A and ST2A function as band-stop filters similarly to the stubs ST1 and ST2 in the antenna module 100. Therefore, the line length of each of the stubs ST1A and ST2A is set to 1 / 2 of the wavelength corresponding to the frequency to be blocked.

[0048] More specifically, the line length L1A of the stub ST1A is set to be equal to or longer than the wavelength λ of the high-frequency signal in the second frequency band supplied to the feed line 142. ２ Then, L1A = λ ２ Similarly, the line length L2A of the stub ST2A is set to λ / 2. １ Then, L2A = λ １ In addition, when the length of one side of the radiating element 121 is Lp, the length is set so as to satisfy L1A<Lp<L2A.

[0049] In this way, even when a short stub is used as a bandstop filter, it is possible to realize a dual-band type antenna module using a common radiating element while ensuring isolation between the power supply wirings 141 and 142 and suppressing degradation of the antenna characteristics.

[0050] However, in the case of a short stub, the line length of the stub is longer than in the case of the open stub of embodiment 1. Therefore, if it is necessary to reduce the size of the entire device, it is more advantageous to use the open stub of embodiment 1.

[0051] The "stub ST1A" and the "stub ST2A" in the first modification correspond to the "first band-stop filter" and the "second band-stop filter" in the present disclosure, respectively.

[0052] (Modification 2) Fig. 6 is a plan view of an antenna module 100B according to modification 2. In antenna module 100B, stubs ST1 and ST2 in antenna module 100 of Fig. 2 are replaced with filters FLT1 and FLT2, respectively. The other configuration of antenna module 100B is the same as that of antenna module 100, and description of elements that overlap with those of antenna module 100 will not be repeated.

[0053] 6, each of the filters FLT1 and FLT2 is an LC resonator in which an inductor and a capacitor are connected in series. One end of the inductor of the filter FLT1 is connected to the power supply line 141, and the other end is connected to the ground electrode GND via a capacitor. Similarly, one end of the inductor of the filter FLT2 is connected to the power supply line 142, and the other end is connected to the ground electrode GND via a capacitor.

[0054] The inductance value of the inductor and the capacitance value of the capacitor of the filter FLT1 are set so that the resonant frequency of the filter FLT1 is the center frequency of the high-frequency signal supplied to the power supply line 142. Similarly, the inductance value of the inductor and the capacitance value of the capacitor of the filter FLT2 are set so that the resonant frequency of the filter FLT2 is the center frequency of the high-frequency signal supplied to the power supply line 141.

[0055] By setting the resonance frequencies of the LC resonators of the filters FLT1 and FLT2 in this way, the filters FLT1 and FLT2 function as band-stop filters for high-frequency signals supplied by the power supply wiring of the other side.

[0056] When the frequency band of the radio waves to be radiated is relatively low, using a stub as in the first embodiment and the first modification increases the line length, which may hinder the miniaturization of the dielectric substrate and may cause a decrease in antenna characteristics due to a large effect on the electric field lines generated between the radiating element and the ground electrode. In such cases, the above-mentioned problems can be addressed by using an LC filter provided outside the dielectric substrate as a band-stop filter.

[0057] The "filter FLT1" and the "filter FLT2" in the second modification correspond to the "first band-stop filter" and the "second band-stop filter" in the present disclosure, respectively.

[0058] (Modification 3) In Modification 3 and Modifications 4 and 5 described later, other aspects of the layout of the power supply wiring will be described.

[0059] 7 is a plan view of an antenna module 100C of Modification 3. In the antenna module 100 of Embodiment 1, the power feed lines 141 and 142 are arranged to extend in opposite directions from the feed point in a direction (X-axis direction) perpendicular to the polarization direction (Y-axis direction) of the radio waves radiated from the radiating element 121 when viewed in a plan view from the normal direction of the dielectric substrate 130. In the antenna module 100C, the power feed lines 141 and 142 are arranged to extend in opposite directions from the feed point in the same direction as the polarization direction (i.e., the Y-axis direction).

[0060] Even with such an arrangement of the power supply lines, the separation distance between the power supply lines 141 and 142 can be ensured, and therefore, the power supply lines can be prevented from being coupled to each other.

[0061] 8 is a plan view of an antenna module 100D of Modification 3. In the antenna module 100 of Embodiment 1 and the antenna module 100C of Modification 3, the two power supply lines 141 and 142 are arranged along the same direction. In the antenna module 100D, the two power supply lines 141 and 142 are arranged along directions that intersect with each other.

[0062] More specifically, in the antenna module 100D, the feed line 141 is arranged from the feed point SP1 along the polarization direction (i.e., the Y-axis direction), and the feed line 142 is arranged from the feed point SP2 along a direction perpendicular to the polarization direction (i.e., the X-axis direction). Note that the extension directions of the feed lines 141 and 142 do not necessarily have to be perpendicular to each other as long as they intersect with each other.

[0063] In this way, by arranging the power supply lines from each power supply point in directions that intersect with each other, it is possible to prevent the power supply lines from being coupled to each other.

[0064] Contrary to FIG. 8, the feed line 141 may be arranged along a direction perpendicular to the polarization direction, and the feed line 142 may be arranged along the polarization direction.

[0065] 9 is a plan view of an antenna module 100E according to Modification 5. In the antenna module 100E, the power feed lines 141 and 142 are arranged to extend in the same direction from the power feed points SP1 and SP2. Specifically, in the example of FIG. 9, the power feed lines 141 and 142 are arranged in parallel along the negative direction of the X-axis from the power feed points SP1 and SP2.

[0066] In addition, in the antenna module 100E, when viewed in a plan view from the normal direction of the dielectric substrate 130, a plurality of vias V1 are arranged between the power feed wiring 141 and the power feed wiring 142, extending in the normal direction. The plurality of vias V1 are arranged along the X-axis direction, similar to the power feed wirings 141 and 142, and are connected to the ground electrode GND. This allows the plurality of vias V1 to function as a shield. Therefore, even if, for example, design constraints require the power feed wirings to be arranged in parallel in the same direction from the radiating element, it is possible to prevent the power feed wirings 141 and 142 from coupling with each other.

[0067] (Modification 6) In Modification 6, another aspect of the matching element for impedance matching with the radiating element will be described.

[0068] 10 is a plan view of an antenna module 100F according to Modification 6. In the antenna module 100F, plate electrodes 151A and 152A connected to the power supply lines 141 and 142, respectively, are provided instead of the stubs 151 and 152 that function as matching elements in the antenna module 100 according to Embodiment 1.

[0069] Each of the plate electrodes 151A and 152A is disposed opposite the ground electrode GND, and a capacitor is formed between the plate electrodes 151A and 152A and the ground electrode GND. By changing the area of ​​each plate electrode and adjusting the capacitance value, it is possible to match the impedance between the corresponding feed wiring and the radiating element 121.

[0070] As with the stubs 151 and 152 in the antenna module 100, the plate electrodes 151A and 152A are not necessarily required components, and if the desired impedance can be achieved by adjusting the connection positions of the stubs ST1 and ST2, the plate electrodes 151A and 152A do not have to be provided.

[0071] Each of the "plate electrode 151A" and the "plate electrode 152A" in Modification 6 corresponds to the "matching element" in the present disclosure.

[0072] (Variation 7) In Variation 7, a configuration in which impedance is adjusted depending on the position of the feed point in radiating element 121 will be described.

[0073] Fig. 11 is a plan view of an antenna module 100G according to Modification 7. In the antenna module 100G, the distance from the center CP of the radiating element 121 to a feed point SP1 on the low frequency side is different from the distance from the center CP to a feed point SP2 on the high frequency side. In the example of Fig. 11, the feed point SP1 is located closer to the center CP than the feed point SP2, and is positioned closer to the end of the radiating element 121. In the polarization direction, the electric field becomes stronger the closer to the end of the radiating element 121, and therefore the impedance increases the closer the feed point is to the end of the radiating element 121.

[0074] Therefore, instead of or in addition to the connection positions of stubs ST1 and ST2 to the feed wiring and matching elements such as stubs 151 and 152, the desired impedance can also be adjusted by the positions of feed points SP1 and SP2 on radiating element 121.

[0075] (Modification 8) In Modification 8 and Modifications 9 and 10 described below, a mode in which power is fed to the radiating element by capacitive coupling will be described.

[0076] Fig. 12 is a plan view of an antenna module 100J according to Modification 8. Fig. 13 is a side perspective view of the antenna module 100J as viewed from the X-axis direction. The antenna module 100J has a configuration in which plate electrodes 171 and 172 are added to the antenna module 100 according to Embodiment 1.

[0077] 12 and 13, the plate electrodes 171 and 172 have a circular shape when the dielectric substrate 130 is viewed in a plan view from the Z-axis direction, and overlap with the feed points SP1 and SP2 of the radiating element 121. As shown in Fig. 13, the plate electrodes 171 and 172 are arranged on a dielectric layer close to the lower side of the radiating element 121 at positions facing the feed points SP1 and SP2, with a gap between them. The feed wiring 141 is connected to the plate electrode 171, and the feed wiring 142 is connected to the plate electrode 172.

[0078] When high frequency signals are supplied to the power supply wirings 141 and 142, the high frequency signals are transmitted to the power supply points SP1 and SP2, respectively, due to capacitive coupling between the plate electrodes 171 and 172 and the radiating element 121.

[0079] Even in such a power supply method, by providing a band-stop filter for each power supply line that prevents the passage of signals in the frequency band supplied to the other power supply line, it is possible to ensure isolation between the power supply lines 141 and 142 and to suppress degradation of antenna characteristics due to signal leakage.

[0080] (Modification 9) Fig. 14 is a plan view of an antenna module 100K according to Modification 9. Fig. 15 is a side perspective view of the antenna module 100K as viewed from the X-axis direction. The antenna module 100K has a configuration in which the plate electrodes 171 and 172 in the antenna module 100J described in Modification 8 are replaced with plate electrodes 171A and 172A.

[0081] 14 and 15, when the dielectric substrate 130 is viewed in a plan view from the Z-axis direction, the plate electrodes 171A and 172A have a generally rectangular shape with the long side along the polarization direction. In the example of Fig. 14, the long side of the plate electrodes 171A and 172A is along the Y-axis. The plate electrode 171A extends in the positive direction of the Y-axis from a position facing the feed point SP1. The plate electrode 172A extends in the negative direction of the Y-axis from a position facing the feed point SP2.

[0082] 15 , the plate electrodes 171A and 172A are arranged on a dielectric layer close to the lower side of the radiating element 121 at positions spaced apart so as to face the feed points SP1 and SP2 of the radiating element 121, respectively. In the plate electrode 171A, a feed wiring 141 is connected at a position that does not overlap with the feed point SP1 when the dielectric substrate 130 is viewed from above. Similarly, in the plate electrode 172A, a feed wiring 142 is connected at a position that does not overlap with the feed point SP2 when the dielectric substrate 130 is viewed from above.

[0083] When a high frequency signal is supplied to the power supply wirings 141 and 142, the high frequency signal is transmitted to the power supply points SP1 and SP2, respectively, due to capacitive coupling between the plate electrodes 171A and 172A and the radiating element 121.

[0084] In this way, by providing an offset in the polarization direction between the position where the corresponding power supply wiring is connected on the plate electrodes 171A and 172A and the power supply position on the radiating element 121, the impedance between the power supply wiring and the radiating element can be adjusted.

[0085] Furthermore, in the antenna module 100K, by providing a bandstop filter for each power supply line that prevents the passage of signals in the frequency band supplied to the opposing power supply line, isolation between the power supply lines 141 and 142 can be ensured and degradation of the antenna characteristics due to signal leakage can be suppressed.

[0086] (Modification 10) Fig. 16 is a plan view of an antenna module 100L of modification 10. Fig. 17 is a side perspective view of the antenna module 100L as viewed from the X-axis direction. The antenna module 100L has a configuration in which the plate electrodes 171 and 172 in the antenna module 100J described in modification 8 are replaced with plate electrodes 171B and 172B.

[0087] 16 and 17, the plate electrodes 171B and 172B have a generally rectangular shape with the long side along the polarization direction when the dielectric substrate 130 is viewed in a plan view from the Z-axis direction. In the example of Fig. 16, the long side of the plate electrodes 171B and 172B is the side along the Y-axis.

[0088] Plate electrodes 171B and 172B are arranged on the same dielectric layer as radiating element 121, with a gap between them. More specifically, plate electrode 171B is arranged to face the center of the side of radiating element 121 that is in the positive direction along the Y axis. Furthermore, plate electrode 172B is arranged to face the center of the side of radiating element 121 that is in the negative direction along the Y axis.

[0089] Further, plate electrode 171B is connected to feed wiring 141, and plate electrode 172B is connected to feed wiring 142. In this case, in radiating element 121, the portion facing plate electrode 171B is feed point SP1, and the portion facing plate electrode 172B is feed point SP2.

[0090] By supplying a high frequency signal to the feed wiring 141, the high frequency signal is transmitted by capacitive coupling via the plate electrode 171B to the feed point SP1 of the radiating element 121. Similarly, by supplying a high frequency signal to the feed wiring 142, the high frequency signal is transmitted by capacitive coupling via the plate electrode 172B to the feed point SP2 of the radiating element 121.

[0091] In this way, by supplying power by capacitive coupling via the plate electrodes 171B, 172B arranged on the same dielectric layer as the radiating element 121, the radiating element 121 and the plate electrodes 171B, 172B for power supply can be arranged on the same dielectric layer, thereby reducing the number of dielectric layers of the dielectric substrate 130.

[0092] Furthermore, in the antenna module 100L, by providing a bandstop filter for each power supply line that prevents the passage of signals in the frequency band supplied to the opposing power supply line, isolation between the power supply lines 141 and 142 can be ensured and degradation of the antenna characteristics due to signal leakage can be suppressed.

[0093] Second Embodiment In a second embodiment, a configuration will be described in which the features of the present invention are applied to a so-called dual-polarized type antenna module that can radiate radio waves in each frequency band in two different polarization directions.

[0094] 18 is a plan view of an antenna module 100H according to embodiment 2. In addition to the configuration of antenna module 100 according to embodiment 1, antenna module 100H is provided with power supply wiring 143 and 144 that transmits high-frequency signals to power supply points SP3 and SP4 of radiating element 121. Description of elements of antenna module 100H that overlap with those of antenna module 100 will not be repeated.

[0095] 18, feed point SP3 is located at a position offset in the negative direction of the X axis from the center of radiating element 121, and feed point SP4 is located at a position offset in the positive direction of the X axis from the center of radiating element 121. When a high-frequency signal is supplied to feed points SP3 and SP4, radio waves polarized in the X axis direction are radiated in the positive direction of the Z axis.

[0096] A feed line 143 for transmitting a high-frequency signal in a first frequency band on the low frequency side is connected to the feed point SP3. The feed line 143 is arranged to extend from the feed point SP3 in the positive direction of the Y axis when viewed in a plan view from the normal direction of the radiating element 121. A stub ST3 that functions as a band-stop filter that prevents the passage of a high-frequency signal in the second frequency band is arranged on the feed line 143. The stub ST3 is an open stub, and its line length is set so that the wavelength of the high-frequency signal in the second frequency band is λ ２ Then λ ２ The power supply wiring 143 may be provided with a stub 153 for adjusting the impedance with the radiating element 121.

[0097] A feed line 144 for transmitting a high-frequency signal in a second frequency band on the higher frequency side is connected to the feed point SP4. When viewed in a plan view from the normal direction of the radiating element 121, the feed line 144 is arranged so as to extend from the feed point SP4 in the negative direction of the Y axis. A stub ST4 that functions as a band-stop filter that prevents the passage of high-frequency signals in the first frequency band is arranged on the feed line 144. The stub ST4 is an open stub, and its line length is set so that the wavelength of the high-frequency signal in the first frequency band is λ １ Then λ １ The power supply wiring 144 may be provided with a stub 154 for adjusting the impedance with the radiating element 121.

[0098] In this way, by supplying a high-frequency signal in the first frequency band to the feed points SP1 and SP3 and a high-frequency signal in the second frequency band to the feed points SP2 and SP4, radio waves with polarization directions in the X-axis direction and the Y-axis direction for each frequency band can be radiated from the radiating element 121.

[0099] Stubs ST1 and ST3 that block the passage of signals in the second frequency band are arranged on the power feed lines 141 and 143, respectively, and stubs ST2 and ST4 that block the passage of signals in the first frequency band are arranged on the power feed lines 142 and 144, respectively. This makes it possible to radiate radio waves in two frequency bands in two polarization directions using a common radiating element while ensuring isolation between the power feed lines. Note that the antenna module 100H can also radiate radio waves in two frequency bands in two polarization directions simultaneously.

[0100] Furthermore, the features of the above-described first to seventh modifications can be applied to the power supply wirings 143 and 144 as appropriate within the scope of not causing any contradiction.

[0101] The "power supply line 143" and the "power supply line 144" in the second embodiment correspond to the "third power supply line" and the "fourth power supply line" in the present disclosure, respectively. The "stub ST3" and the "stub ST4" in the second embodiment correspond to the "third band-stop filter" and the "fourth band-stop filter" in the present disclosure, respectively.

[0102] Third Embodiment In a third embodiment, a configuration will be described in which high-frequency signals in two frequency bands are supplied to one feeding point of a radiating element via a diplexer.

[0103] 19 is a plan view of antenna module 100I according to embodiment 3. Radiating element 121 of antenna module 100I has feed point SPA disposed at a position offset in the positive direction of the X axis from the center of radiating element 121, and feed point SPB disposed at a position offset in the negative direction of the Y axis from the center of radiating element 121. Feed line 145A is connected to feed point SPA, and feed line 145B is connected to feed point SPB.

[0104] When viewed from above in the normal direction of the radiating element 121, the feed line 145A extends from the feed point SPA in the positive direction of the X-axis, branches into two directions at a branch node NA, and is connected to a terminal TL1 and a terminal TH1. A high-frequency signal in a first frequency band on the low frequency side is supplied to the terminal TL1. A high-frequency signal in a second frequency band on the high frequency side is supplied to the terminal TH1.

[0105] A stub STH1 that functions as a band-stop filter for preventing high-frequency signals in the second frequency band from passing is connected to the line between the terminal TL1 and the branch node NA. Also, a stub STL1 that functions as a band-stop filter for preventing high-frequency signals in the first frequency band from passing is connected to the line between the terminal TH1 and the branch node NA. That is, a diplexer is formed by the stubs STH1 and STL1.

[0106] The stub STH1 prevents a high-frequency signal in the second frequency band from leaking to the terminal TL1. Similarly, the stub STL1 prevents a high-frequency signal in the first frequency band from leaking to the terminal TH1. By supplying a high-frequency signal in the first frequency band to the terminal TL1 and a high-frequency signal in the second frequency band to the terminal TH1, radio waves in two frequency bands with the polarization direction in the X-axis direction can be radiated from the radiating element 121.

[0107] In other words, the above configuration can be interpreted as a configuration in which the power supply lines 141 and 142 in the first embodiment are connected to the same power supply point.

[0108] When viewed from above in the normal direction of the radiating element 121, the feed line 145B extends from the feed point SPB in the negative direction of the Y axis, branches into two directions at a branch node NB, and is connected to a terminal TL2 and a terminal TH2. A high-frequency signal in a first frequency band on the low frequency side is supplied to the terminal TL2. A high-frequency signal in a second frequency band on the high frequency side is supplied to the terminal TH2.

[0109] A stub STH2 that functions as a band-stop filter for preventing high-frequency signals in the second frequency band from passing is connected to the line between the terminal TL2 and the branch node NB. Also, a stub STL2 that functions as a band-stop filter for preventing high-frequency signals in the first frequency band from passing is connected to the line between the terminal TH2 and the branch node NB. That is, a diplexer is formed by the stubs STH2 and STL2.

[0110] The stub STH2 prevents the high-frequency signal of the second frequency band from leaking to the terminal TL2. Similarly, the stub STL2 prevents the high-frequency signal of the first frequency band from leaking to the terminal TH2. By supplying the high-frequency signal of the first frequency band to the terminal TL2 and the high-frequency signal of the second frequency band to the terminal TH2, the radiating element 121 can radiate radio waves of two frequency bands with the polarization direction in the Y-axis direction.

[0111] With the above configuration, the antenna module 100I can radiate radio waves in two frequency bands in two polarization directions using a common radiating element. Furthermore, by providing stubs STL1, STL2, STH1, and STH2 that function as band-stop filters, leakage of high-frequency signals supplied to each power supply line can be suppressed.

[0112] Although not shown in FIG. 19, the power supply lines 145A and 145B may be provided with matching elements for adjusting the impedance between each power supply line and the radiating element 121.

[0113] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims.

[0114] 10 Communication device, 100, 100A to 100L Antenna module, 110 RFIC, 111A to 111H, 113A to 113H, 117A, 117B Switch, 112AR to 112HR Low noise amplifier, 112AT to 112HT Power amplifier, 114A to 114H Attenuator, 115A to 115H Phase shifter, 116A, 116B Signal combiner / divider, 118A, 118B Mixer, 119A, 119B Amplifier circuit, 120 Antenna device, 121 Radiating element, 130 Dielectric substrate, 131, 132 Main surface, 141 to 1424, 145A, 145B Power supply wiring, 151 to 154, ST1 to ST4, ST1A, ST2A, STL1, STL2, STH1, STH2 stub, 151A, 152A, 171, 172, 171A, 172A, 171B, 172B plate electrode, 160 solder bump, 200 BBIC, CP center, FLT1, FLT2 filter, GND ground electrode, NA, NB branch node, P1 to P8, TH1, TH2, TL1, TL2 terminal, SP1 to SP4, SPA, SPB power supply point, V1 via.

Claims

1. An antenna module comprising: a flat-shaped radiating element; a ground electrode arranged opposite the radiating element; a first feed wiring that transmits high-frequency signals in a first frequency band to a first feed point of the radiating element; a second feed wiring that transmits high-frequency signals in a second frequency band higher than the first frequency band to a second feed point of the radiating element; a first bandstop filter connected to the first feed wiring and configured to prevent the passage of high-frequency signals in the second frequency band; and a second bandstop filter connected to the second feed wiring and configured to prevent the passage of high-frequency signals in the first frequency band.

2. The antenna module described in claim 1, wherein each of the first bandstop filter and the second bandstop filter is a stub having one end connected to a corresponding power supply wiring, and the line length of the first bandstop filter is shorter than the line length of the second bandstop filter.

3. The antenna module described in claim 2, wherein each of the first bandstop filter and the second bandstop filter is an open stub with the other end open, the first feeding point is located at a position offset in a first direction from the center of the radiating element, the second feeding point is located at a position offset in a second direction from the center of the radiating element, 1 / 2 of the length of the radiating element along the first direction is longer than the line length of the first bandstop filter, and 1 / 2 of the length of the radiating element along the second direction is shorter than the line length of the second bandstop filter.

4. The antenna module described in claim 2, wherein each of the first bandstop filter and the second bandstop filter is a short stub having the other end connected to the ground electrode, the first feeding point is located at a position offset in a first direction from the center of the radiating element, the second feeding point is located at a position offset in a second direction from the center of the radiating element, the length of the radiating element along the first direction is longer than the line length of the first bandstop filter, and the length of the radiating element along the second direction is shorter than the line length of the second bandstop filter.

5. The antenna module according to claim 3 or 4, wherein the second direction is opposite to the first direction with respect to the center of the radiating element.

6. The antenna module according to claim 3 or 4, wherein the second direction is a direction intersecting the first direction at the center of the radiating element.

7. An antenna module as described in any one of claims 3 to 6, further comprising a dielectric substrate on which the radiating element and the ground electrode are arranged, wherein, when a wavelength in the dielectric substrate of a signal corresponding to the first frequency band is a first wavelength and a wavelength in the dielectric substrate of a signal corresponding to the second frequency band is a second wavelength, the length of the radiating element along the first direction is shorter than 1 / 2 of the first wavelength, and the length of the radiating element along the second direction is longer than 1 / 2 of the second wavelength.

8. An antenna module according to any one of claims 2 to 7, wherein the distance from the center of the radiating element to the first feed point is different from the distance from the center of the radiating element to the second feed point.

9. The antenna module according to claim 1, wherein each of the first bandstop filter and the second bandstop filter is an LC filter.

10. An antenna module described in any one of claims 1 to 9, wherein, when viewed in a plane from the normal direction of the radiating element, the extension direction of the first power supply wiring from the first power supply point is different from the extension direction of the second power supply wiring from the second power supply point.

11. The antenna module according to any one of claims 1 to 10, further comprising a matching element provided on at least one of the first feed wiring and the second feed wiring.

12. The antenna module according to claim 11, wherein the matching element is a stub having one end connected to a corresponding feed line.

13. The antenna module according to claim 11, wherein the matching element is a flat plate electrode connected to a corresponding power supply wiring and disposed so as to face the ground electrode.

14. An antenna module as described in any one of claims 1 to 13, further comprising a power supply circuit configured to output a high-frequency signal to the first power supply wiring and the second power supply wiring, wherein the power supply circuit outputs a high-frequency signal to the first power supply wiring and the second power supply wiring individually.

15. The antenna module according to claim 1, further comprising: a third feed wiring that transmits high frequency signals in the first frequency band to a third feed point of the radiating element; a fourth feed wiring that transmits high frequency signals in the second frequency band to a fourth feed point of the radiating element; a third bandstop filter connected to the third feed wiring and configured to prevent passage of high frequency signals in the second frequency band; and a fourth bandstop filter connected to the fourth feed wiring and configured to prevent passage of high frequency signals in the first frequency band, wherein the first feed point is located at a position offset in a first direction from the center of the radiating element, the second feed point is located at a position offset with respect to the center of the radiating element in a second direction opposite to the first direction, the third feed point is located at a position offset in a third direction intersecting the first direction at the center of the radiating element, and the fourth feed point is located at a position offset in a fourth direction opposite to the third direction with respect to the center of the radiating element.

16. A communication device equipped with an antenna module according to any one of claims 1 to 15.

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