JP2001345736A - Apparatus sharing antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To overcome the problem of a conventional apparatus sharing an antenna such that the occurrence of double higher-harmonic waves arising in a switching circuit during OFF is unavoidable, by the inside leakage of a high-output signal attendant upon the downsizing in a mobile radio terminal sharing an antenna. SOLUTION: An optimum resonance circuit is constituted to suppress the occurrence of double higher harmonic waves, by adding C and L in parallel to a switching circuit on the side of a system relatively higher in frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna duplexer for a mobile radio terminal constituted by a surface acoustic wave (SAW) filter, or a combination of a SAW filter and a high-frequency switch, or an onboard duplexer. Mobile radio terminal.

[0002]

2. Description of the Related Art In a mobile radio terminal, means for transmitting and receiving a transmission signal and a reception signal corresponding to one system by sharing one antenna is essential. Conventionally, as the above-mentioned means, it has two different pass frequency bands, a reception frequency band and a transmission frequency band, and in order to prevent and reduce mutual interference, a transmission dielectric resonator and a reception dielectric resonator respectively. An antenna duplexer combining a matching circuit and a phase shift circuit has been used.

[0003] In recent years, small and lightweight mobile radio terminals have been developed, and services that can use mobile radio terminals that process a plurality of systems such as dual band and triple band are also planned. For such a situation,
In the antenna duplexer using the dielectric resonator, since the dielectric resonator itself is large, heavy, and a three-dimensional circuit wiring, there is a limit in reducing the size and weight of the antenna duplexer and the mobile wireless terminal. Therefore, instead of the dielectric resonator, S
By adopting a combination of an AW filter or a SAW filter and a high-frequency switch, the main components can be reduced in size and weight, and the arrangement and configuration of the components can be taken into consideration. Proposals have been made to reduce the weight and weight.

[0004]

However, such common use of antennas and miniaturization and weight reduction, on the other hand, have adverse effects due to leakage of transmission signals between dual-band systems.

[0005]

SUMMARY OF THE INVENTION According to the present invention, the leakage of a transmission signal, which is a problem in the miniaturized duplexer described above, is achieved by using a switching element of a higher frequency band system.
In the F state, paying attention to the fact that it is caused by non-linear distortion due to self-detection operation when a strong signal is input from a low frequency band system, a series resonance circuit is added to the switching element of the higher frequency band system. As a configuration of parallel connection, leakage of a transmission signal is suppressed.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In recent years, development of mobile radio terminals represented by small and lightweight portable telephones has been progressing at a rapid pace. On the other hand, a conventional FDMA (Frequency
Division Multiple Access) or TDMA (Time Divi
CDMA (Code Div.
Ision Multiple Access) services are also being planned. Further, different systems or systems are operated in different countries or regions. For example, in Europe, the FDMA ETACS (Extended Total Access Communication) is used.
System) System and TDMA GSM (Global Sys
tem for Mobile Communication) system, EGSM (E
xtended Global System for Mobile Communication) system and PCN (Personal Communication Network) system service. In North America, FDMA EAMPS (Extended Advanced Mobile Phone Serv
ice) system and TDMA PCS (Personal Commun
icationSystem)
In Japan, the FDMA system NTACS (New Total Access
Communication System) System and TDMA PD
C (Personal Digital Cellular) system services are provided.

Conventionally, in a mobile radio terminal corresponding to each system, an antenna duplexer using a dielectric resonator has been used. However, the area and volume of the dielectric resonator itself is large, and even if the components are arranged, It is difficult to meet the recent demand for miniaturization. Therefore, by employing a SAW filter or a combination of a SAW filter and a high-frequency switch in place of the dielectric resonator, the main components can be reduced in size and weight, and the arrangement and configuration of the components can be taken into consideration. Proposals have been made to drastically reduce the size and weight of devices and mobile wireless terminals (for example,
Japanese Patent Application No. 10-364074), on the other hand, has an adverse effect due to leakage of transmission signals between dual-band systems.

Hereinafter, the present invention which has been made to solve the above-mentioned problem will be described in detail based on embodiments shown in the drawings.

First, as an example of the frequency allocation of a typical mobile communication system in FIG. 1, (a) shows an EGSM system put to practical use mainly in Europe, (b) shows a DCS system, and (c) PCs that have been put to practical use mainly in North America
3 shows the frequency allocation of the S system. Here, f _T indicates a transmission frequency band, and f _R indicates a reception frequency band. As shown in (b) in the figure, the twice frequency of the transmission signal band of EGSM partially overlaps with the transmission and reception frequency of DCS. When realizing a dual or triple multi-band terminal of a combination of systems having such a frequency arrangement, the intensity of the second harmonic of the EGSM transmission signal radiated from the antenna is set to E.
It is necessary to keep the transmission signal of GSM at -71 dB or less, and it is very difficult with the prior art to achieve both miniaturization and suppression of the second harmonic.

FIG. 2 is a circuit block diagram related to transmission and reception of an antenna duplexer to which the present invention is applied. As a specific system, here, an EGSM system (transmission signal frequency from 880 MHz to 915 MHz) and a DCS system (transmission signal frequency from 1710 MHz to 1785 MHz)
The configuration of the dual-band terminal antenna duplexer will be described. 1 is an EGSM transmission terminal, 2 is an EGSM transmission switching circuit, 3 is a low-pass filter, 4 is an antenna terminal,
5 is a high-pass filter, 6 is a DCS transmission switching circuit, and 7 is a DCS transmission terminal. 8 is S for EGSM reception
AW filter, 9 is a DCS receiving SAW filter, 10
Is an EGSM receiving terminal, and 11 is a DCS receiving terminal.

At the time of transmission of the EGSM system, a transmission signal is input from the transmission terminal 1 of the EGSM,
Since the bias of the transmission switching circuit 2 is turned on, the transmission signal of EGSM passes through the EGSM transmission switching circuit, and passes through the low-pass filter 3 designed to pass the EGSM band and the DCS band to the stop band. And reaches the antenna 4. The antenna 4 is connected to the low-pass filter 3 and also to the high-pass filter 5 designed to pass the DCS band and the EGSM band to the stop band. 6
Are connected to reach the DCS transmission terminal 7. The transmission signal of the EGSM reaching the antenna passes through the high-pass filter 5.
In principle, it does not go around the DCS side circuit due to the reflection characteristics. On the other hand, during transmission of the DCS system, a transmission signal is input from the transmission terminal 7 of the DCS, and the bias of the DCS transmission switching circuit 6 is turned on.
The DCS transmission signal passes through a DCS transmission switching circuit, passes through a high-pass filter 5 designed with a DCS band as a pass band, and a EGSM band with a stop band, and reaches an antenna 4. In this case as well, due to the pass / reflection characteristics of the low-pass filter 3, the signal does not go around the circuit on the EGSM side in principle.

When receiving the EGSM system, the antenna 4
The EGSM signal received at passes through the low-pass filter 3, passes through the EGSM receiving SAW filter 8,
It reaches the SM receiving terminal 10. On the other hand, during reception of the DCS system, the DCS signal received by the antenna 4 passes through the high-pass
And reaches the EGSM receiving terminal 10.

As described above, regarding transmission, EGSM, D
Turn on / off the bias of either CS switching circuit
Dual band operation is realized by performing FF.
On the other hand, regarding reception, selection by a filter is performed, so that it is not necessary to perform an ON / OFF operation such as transmission.

It should be noted here that OF
When a strong signal is input to the switching element in the F state, non-linear distortion occurs due to the self-detection operation.
As described in the block diagram of FIG. 2, the low-pass filter 3 prevents the transmission signal of the EGSM from leaking to the circuit on the DCS side, and the high-pass filter 3 prevents the transmission signal of the DCS from leaking to the EGSM side. Since the filter 5 is connected, no strong signal is input to the switching circuit in the OFF state in principle.

However, as the size of the entire circuit is reduced, the space between the components becomes smaller, and the signal leaks over the filter. A particularly fatal problem is the EGSM transmission signal generated by the non-linearity from the switching circuit on the DCS side during EGSM transmission.
The problem is that a signal having twice the frequency component is radiated from the antenna simultaneously with the EGSM transmission signal. In the GSM system, the second harmonic emitted from the antenna is -71 of the fundamental wave.
It is defined as dB or less, and it is very important to solve this problem. The simplest solution is to prevent the signal from leaking out by making the space between the components sufficient, but this is against the demand for miniaturization. Of course, such a problem does not occur if the switching circuit is constituted by a switch of a type that is structurally opened and closed, but it is turned on by the presence or absence of a starting current as described in Japanese Patent Application No. 10-364074. When the switch is controlled to be OFF, it is inevitable that a signal having twice the frequency component of the EGSM transmission signal is generated due to the nonlinearity of the switching element. That is, the transmission signal (approximately 35 dBm) input from the transmission terminal 1 of the EGSM reaches the antenna 4 after passing through the EGSM transmission switching circuit 2, but a part of this signal jumps over the high-pass filter 5 and is transmitted by the DCS transmission switching. Circuit 6 is reached. At this time, since the bias of the second switching circuit 6 is OFF, a signal having twice the frequency of the EGSM transmission signal is generated due to the non-linear effect of the switching circuit 6. Since the generated double frequency signal (1760-1830 MHz) is included in the DCS transmission / reception band (1710-1880 MHz), it passes without being blocked by the high-pass filter 5, and is transmitted from the antenna 4 together with the fundamental wave of EGSM. Will be released.

This phenomenon depends on the termination condition of the DCS transmission terminal 7, and it is necessary to suppress the generation of the second harmonic to a specified value or less under any termination condition. In the system standard, as shown in FIG. 3, the intensity of the frequency twice as high as that of the transmission signal is determined to be suppressed to −36 dBm or less, and the intensity of the fundamental wave (approximately 35 dBm) and the standard value of the second harmonic −36 dBm. Must be satisfied, which is the difference of −71 dB.

Referring to FIG. 4, a description will be given of the result of an experiment conducted by the antenna duplexer shown in FIG. 2 for measuring the intensity of occurrence of a frequency twice as high as that of the EGSM transmission signal. In FIG. 4, EGSM
A high-output oscillator 101 is connected to the transmission terminal 1 via a low-pass filter 102, and a spectrum analyzer 104 for measuring a signal output from the antenna is connected to the antenna terminal 4 via a high-pass filter 103,
The phase shifter 105 for adjusting the termination condition of the transmission terminal 7 is connected to the DCS transmission terminal 7. Each receiving terminal 10, 11 is terminated at 50 ohms. Here, one of the phase shifters 105 is short-circuited. The high-pass filter 103 suppresses nonlinear distortion inside the spectrum analyzer 104 by suppressing a high-output EGSM transmission signal.

An EGSM transmission signal of approximately +35 dBm is input to the EGSM transmission terminal 1. EGSM transmission switching circuit 2 is turned on, DCS transmission switching circuit 6
Was turned off, the phase shifter 105 was adjusted while changing the EGSM transmission signal (from 880 MHz to 915 MHz), and the second harmonic output of the largest EGSM transmission signal was measured.

FIG. 5 shows the measurement results. The vertical axis represents the fundamental wave output (+35 dBm) of the EGSM and the observed second harmonic (2f
The output Pout at _T ) is displayed in dBc. The horizontal axis is twice the frequency (1760M) of the input EGSM transmission signal.
Hz to 1830 MHz). As is clear from this figure, by employing a SAW filter or a combination of a SAW filter and a high-frequency switch, the main components can be reduced in size and weight, and
In consideration of the arrangement and configuration of the components, and aiming for drastic miniaturization and weight reduction of the antenna duplexer and the mobile radio terminal, -71 dB specified in the standard is required.
May not be satisfied.

In order to prevent the transmission of the EGSM transmission signal leaking into the DCS transmission switching circuit 6, it is sufficient to simply increase the size of the circuit, but this contradicts the requirement for miniaturization.

FIG. 6 is a diagram showing an embodiment of an improvement of a switching element (eg, a PIN diode) which is a key of the present invention. That is, the capacitive element C ₁ is connected in parallel between the terminals of the switching element which is turned off during the transmission of the EGSM.
Connecting the inductive element L ₁ and. Here, C ₀ is a stray capacitance existing between terminals of the switching element. A resonance circuit composed of these elements C ₀ , C ₁ , and L ₁ is formed, and this resonance circuit is expressed by an EGSM transmission signal as shown in FIG. 7 in which the horizontal axis represents frequency and the vertical axis represents impedance. The value of each element is selected so as to cause an impedance state of short circuit due to series resonance and an infinite impedance state due to parallel resonance at the second harmonic. Of course, the stray capacitance C ₀
It is not possible to control the value of, so there is no other way than to use the measured result as it is. In FIG. 7, the impedance characteristic is shown by one line. An actual mobile radio terminal uses an arbitrary frequency in the EGSM frequency band when viewed instantaneously. Depending on the frequency used, a short circuit or infinity may occur in a strict sense. Although not necessarily, the horizontal axis of FIG. 7 is extremely compressed, so that the EGSM can have a predetermined impedance characteristic without any problem, regardless of where it is used in the EGSM frequency band. . In other words, the mobile radio terminal is used in an environment in which the ambient temperature fluctuates to some extent, but it can be said that the degree does not matter. Therefore, the values of the capacitive element C ₁ and the inductive element L ₁ set in accordance with the following equation may be determined based on the center frequency of the EGSM frequency band.

A resonance circuit according to the present invention is formed between the terminals of the switching element, and a series resonance is generated by an EGSM transmission signal.
When the value of each element is selected so as to cause parallel resonance at the second harmonic, the DCS transmission switching circuit 6 described in FIG.
Even if a GSM transmission signal leaks, a non-linear distortion does not occur because a short-circuit state is realized at that frequency. Of course, there is no problem at frequencies twice as high as the EGSM transmission signals to be transmitted and received, that is, in the vicinity of the DCS transmission signal band since parallel resonance occurs.

The capacitance between the terminals of the switching element is represented by C ₀ , E
Conditions for the series resonance of the GSM transmission signal frequency f _T to the f _T is generated is expressed by equation (1), twice conditions for parallel resonance at the frequency 2f _T occurs in the transmission signal frequency of the EGSM Is represented by (Equation 2).

[0024]

(Equation 1)

[0025]

(Equation 2)

From (Equation 1) and (Equation 2), the values of C ₁ and L ₁ can be obtained as (Equation 3) and (Equation 4), respectively.

[0027]

(Equation 3)

[0028]

(Equation 4)

Here, f _T is, as described above, EGS
This is the center frequency of the M frequency band.

FIG. 8 is a diagram showing a measuring system for confirming the effect of the present invention. The circuit shown in FIG.
_1, L ₁ is only added points are different, the operation for the circuit arrangement and evaluation are the same as described in FIG.

FIG. 9 is a diagram showing the measurement results according to FIG. In the figure, the characteristic denoted by reference numeral 200 is shown in FIG. 8, and for comparison, the elements C ₁ ,
The results of before you add the L ₁ is shown. As is clear from FIG. 9, the signal strength twice as high as that of the EGSM is reduced from 15 dBc to about 30 dBc as compared with the level before the countermeasure, and the -71 dB required from the standard is cleared with a margin. You can see that there is. In FIG. 9, 1820 MHz
The reason why data is not obtained in a frequency region exceeding the above range is presumed to be that the signal intensity has a level at which the sensitivity of the spectrum analyzer 104 does not exist in this frequency region. Furthermore, these values are the results under the worst termination conditions at each frequency by adjusting the phase shifter 105 attached to the DCS transmission terminal 7, and show that the specifications can be satisfied under all termination conditions. .

FIG. 10 is a circuit block diagram relating to transmission and reception when the present invention is applied to a triple band mobile radio terminal sharing an antenna. As a specific system, here, an EGSM system (transmission signal frequency 880 MHz)
To 915 MHz), DCS system (transmission signal frequency from 1710 MHz to 1785 MHz) and PCS system (transmission signal frequency from 1850 MHz to 1910 MH)
The configuration of the triple-band terminal antenna duplexer z) will be described. Here, those designated by reference numerals 1 to 11 are shown in FIG.
It has the same function as the one described in. However,
In this example, the PCS transmission terminal is shared with the DCS transmission terminal 7. The DCS receiving system is connected to the high-pass filter 5 via the λ / 4 line 15. Further, the connection point between the λ / 4 line 15 and the DCS receiving SAW filter 9 is
CS receiving SAW filter 12 and PCS receiving terminal 1
3 and a switching element 2 in which a capacitive element C ₁ and an inductive element L ₁ are connected in parallel.
0 is connected to one end, and the other end of the switching element 20 is grounded.

In this embodiment, when transmitting / receiving by the EGSM system, the switching elements 2 and 20 are turned on,
The switching element 6 is turned off, the switching element 6 is turned on when transmitting / receiving by the DCS system, the switching elements 2 and 20 are turned off, and the switching element 6 is turned on / off when transmitting / receiving by the PCS system.
N, the switching elements 2 and 20 are turned off.
Even in this case, the switching element 6 or 20 that is turned off is short-circuited and infinitely impedance due to the capacitive element C ₁ and the inductive element L ₁ connected in parallel. There is no.

In the above description, the circuit board or the circuit element is not specifically described. However, as described in the above-mentioned Japanese Patent Application No. 10-364074, the circuit board is composed of a signal pattern, a ground pattern and Assuming that the multilayer substrate has at least two layers of dielectrics on which a bias pattern is formed, at least one or more layers of the substrate are removed from under the multilayer substrate, and a part of the substrate is removed. At least one SAW filter is mounted on the signal pattern and the ground pattern formed on the other exposed substrate surface, and in a space formed by removing a part of the substrate. At least one lumped-constant circuit element is mounted on the upper surface of the upper substrate, and a signal terminal pattern and a signal terminal for connection to the outside are provided on the lower surface of the remaining lower substrate. To form a fine-ground terminal pattern,
By adopting a structure in which these connection terminals are connected to the signal pattern and the ground pattern of each layer, further miniaturization can be achieved. The leakage of the transmission signal due to miniaturization and capacitive element C ₁ connected to the switching element also becomes pronounced inductive element L ₁ problem with nonlinear characteristics can be prevented.

Although the above-described capacitive element C ₁ and inductive element L ₁ have been described as lumped circuit elements, the laminated capacitance or the gap capacitance formed on the substrate described in Japanese Patent Application No. 10-364074 is also described. Any one of them and an inner layer inductor, a helical coil, or a distributed constant line, which is formed on the substrate, may be used.

In the above description, the specific frequency arrangement has been described using examples of EGSM and DCS.
The frequency arrangement to which the present invention can be applied is not limited to this. For a multi-band mobile communication terminal using a plurality of different frequency bands, a frequency band twice as high as one frequency band overlaps with another frequency band. What works is obvious.

[0037]

According to the present invention, two frequency bands of one frequency band can be used.
The antenna duplexer for mobile radio terminals corresponding to a plurality of systems in which the double frequency band overlaps with another frequency band can be extremely miniaturized, and the double harmonic generated by the nonlinear distortion of the switching circuit can be suppressed. .

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a transmission / reception frequency arrangement for each active system.

FIG. 2 is a circuit block diagram relating to dual band transmission / reception of an antenna duplexer to which the present invention is applied.

FIG. 3 is a diagram illustrating a standard for suppressing double harmonics in dual band transmission / reception of an antenna duplexer.

FIG. 4 is a diagram showing an example of a circuit block for measuring generation of a second harmonic in dual-band transmission / reception of an antenna duplexer.

FIG. 5 is a diagram showing an example of an experimental result of generation of a second harmonic of a conventional configuration in dual band transmission / reception by an antenna duplexer.

FIG. 6 is a diagram showing an equalizing circuit of a resonance circuit which is a feature of the present invention.

FIG. 7 is a diagram showing impedance characteristics of an equivalent circuit which is a feature of the present invention.

FIG. 8 is a diagram showing an example of a circuit block for measuring second harmonic generation according to an embodiment of the present invention in dual band transmission / reception of the antenna sharing device.

FIG. 9 is a diagram showing an example of an experimental result of generation of a second harmonic according to an embodiment of the present invention in dual band transmission / reception of the antenna duplexer.

FIG. 10 is a diagram showing an embodiment of a block configuration in which the present invention is applied to a triple band system of an antenna duplexer.

[Explanation of symbols]

1: EGSM transmission terminal, 2: EGSM transmission switching circuit, 3: low-pass filter, 4: antenna terminal, 5:
High-pass filter, 6: DCS transmission switching circuit,
7: DCS transmission terminal, 8: EGSM reception SAW filter, 9: DCS reception SAW filter, 10: EGSM
Receiving terminal, 11: DCS receiving terminal, 12: PCS receiving SAW filter, 13: PCS receiving terminal, 15: λ / 4
Line, 20: switching circuit, 101: high-power oscillator, 102: low-pass filter, 103: high-pass filter, 104: spectrum analyzer, 105: phase shifter.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mitsutaka Hikita 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. Within Hitachi Media Electronics (72) Inventor Naoki Matsuura 1 Kitano, Majo, Mizusawa-shi, Iwate F-term within Hitachi Media Electronics Co., Ltd. (Reference) 5J006 JA31 KA01 KA24 LA03 PB03 5J012 BA03 5J097 AA29 BB15 LL03 5K011 BA03 DA02 DA22 DA27 JA01 KA04

Claims (10)

[Claims] An antenna duplexer used in a system in which a frequency band twice as large as a transmission frequency band of one system overlaps a part of a transmission frequency band of another system,
The transmission switch for each system is composed of a switch whose ON / OFF is controlled depending on the presence or absence of the start-up current. Series resonance is applied to the transmission switch of the system used in the higher frequency band for the frequency in the lower frequency band. antenna duplexer, wherein a series circuit of the inductive element L ₁ is connected to the capacitive element C ₁ to the. 2. The system according to claim 1, wherein the band filter corresponding to the system is S.
The duplexer according to claim 1, wherein the duplexer is an AW filter. 3. A terminal of a transmission terminal corresponding to a system used in a higher frequency band, wherein a signal radiated simultaneously from a system used in a higher frequency band is transmitted by the transmission signal at a frequency in the lower frequency band. 2. The antenna duplexer according to claim 1, wherein regardless of the condition, the intensity of a transmission signal at a frequency in a low frequency band is −71 dB or less. 4. At least three systems share an antenna, and a transmission frequency band twice as high as a transmission frequency band of one of the three systems is used as a transmission frequency of another of the three systems. In an antenna duplexer used in a system that overlaps a part of the band, the transmission switch for each system is configured with a switch whose ON and OFF is controlled depending on the presence or absence of the starting current, and used in a higher frequency band antenna duplexer, wherein a series circuit of the inductive element L ₁ and the capacitive element C ₁ to the series resonance for frequencies lower frequency band to the transmission switch of the system is connected to be. 5. The method according to claim 1, wherein the band filter corresponding to the system is S
The antenna duplexer according to claim 4, which is an AW filter. 6. A terminal of a transmission system terminal corresponding to a system used in a higher frequency band, wherein a signal radiated simultaneously from a system used in a higher frequency band is transmitted by the transmission signal at a frequency in the lower frequency band. 5. The antenna duplexer according to claim 4, irrespective of the condition, the intensity is −71 dB or less with respect to the intensity of a transmission signal at a low frequency band frequency. 7. The capacitance value C ₁ of the capacitive element is set to be approximately three times the stray capacitance C ₀ between the terminals of the switching element, and the inductance value L ₁ of the inductive element is set in the low frequency band. when a transmission signal frequency within the band of the system and f _T1, outline _{L 1 = 1 / 3C 0 (} 2πf T1) 2 claims 1 is set as to the antenna duplexer according to any one of 6. 8. A system in which a frequency band twice as large as a transmission frequency band of one system is used in a system overlapping a part of a transmission frequency band of another system, and a transmission switch for each system is determined by the presence or absence of a starting current. ON, OFF
Is controlled by a switch, and a capacitive element C ₁ that performs series resonance with respect to a frequency in a lower frequency band is provided to a transmission switch of a system used in a higher frequency band.
A series circuit of the inductive element L ₁ is an antenna duplexer which is connected to, the antenna duplexer, the signal pattern for forming the respective system, at least to form the grounding pattern and the bias pattern A multilayer substrate made of a dielectric material having two or more layers, wherein at least a part of the substrate having at least one layer is removed from under the multilayer substrate, and a part of the substrate is removed to form another exposed substrate surface; One or more SAW filters are mounted on the signal pattern and the ground pattern, and in a space formed by removing a part of the substrate, and at least one SAW filter is provided on the upper surface of the uppermost substrate. The lumped constant circuit element is mounted, and a signal terminal pattern for connection to the outside and a ground terminal pattern are formed on the lower surface of the lowermost substrate,
An antenna duplexer wherein the connection terminal is connected to a signal pattern and a ground pattern of each layer. 9. The capacitive element is composed of one of a chip capacitor, a laminated capacitor internally laminated on a substrate, and a gap capacitance, and the inductive element is a chip inductor, a helical coil, a distributed constant line, or an internal layer inductor internally formed on a substrate. The antenna duplexer according to claim 6, wherein the antenna duplexer is configured by any one of the following. 10. A system in which a frequency band twice as large as a transmission frequency band of one system is used in a system overlapping a part of a transmission frequency band of another system, and a transmission switch for each system is determined by the presence or absence of a starting current. ON, OF
A capacitive element C which is constituted by a switch whose F is controlled and which performs series resonance with respect to a frequency in a low frequency band to a transmission switch of a system used in a higher frequency band.
Mobile radio terminals, characterized in that it comprises an antenna _{duplexer 1} and the series circuit of the inductive element L ₁ is connected.