Abstract:
A mobile wireless apparatus wherein matching circuits can be independently designed, while the increase in the circuit scale can be suppressed and the cost can be reduced. In this apparatus, a filter ( 102 ) suppresses a frequency band (f 2 -f 3 ) of signals received by an antenna element ( 101 ). A filter ( 105 ) suppresses a frequency band (f 1 ) of the signals received by the antenna element ( 101 ). A wireless unit ( 104 ) acquires data that is obtained by demodulating the signals obtained by suppressing the frequency band (f 2 -f 3 ) and superimposing the demodulated signals on the signals of the frequency band (f 1 ). A wireless unit ( 107 ) acquires data that is obtained by demodulating the signals obtained by suppressing the frequency band (f 1 ) and superimposing the demodulated signals on the signals of the frequency band (f 2 -f 3 ). A matching circuit ( 103 ), which is connected between the filter ( 102 ) and the wireless unit ( 104 ), matches the impedances of the filter ( 102 ) and wireless unit ( 104 ). A matching circuit ( 106 ), which is connected between the filter ( 105 ) and the wireless unit ( 107 ), matches the impedances of the filter ( 105 ) and wireless unit ( 107 ).

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a portable radio apparatus, and more particularly, to a portable radio apparatus that simultaneously operates a plurality of radio systems by sharing one antenna element. 
       BACKGROUND ART 
       [0002]    In recent years, the number of radio systems mounted on a portable radio apparatus has been ever increasing. Furthermore, in recent years, portable radio apparatuses are becoming smaller in size and thickness and it is therefore more difficult to accommodate as many antenna elements as radio systems mounted in their housings. Therefore, conventionally, such a portable radio apparatus is sharing antenna elements among a plurality of radio systems. That is, the conventional portable radio apparatus is mounted with an antenna element that supports a plurality of radio systems. 
         [0003]    Such a portable radio apparatus shares an antenna element by switching connections between the antenna element and a receiver provided for each radio system using a switch according to the transmitting/receiving radio systems. However, such a portable radio apparatus has a problem of being unable to simultaneously operate a plurality of radio systems. 
         [0004]    As a portable radio apparatus to solve such a problem, a portable radio apparatus is known which shares an antenna element by using filters of different pass frequencies according to a transmitting/receiving radio system (e.g. Patent Literature 1). The portable radio apparatus according to Patent Literature 1 can simultaneously operate a plurality of radio systems. 
       Citation List 
     Patent Literature 
     PTL 1 
     National Publication of International Patent Application No. 2004-523993 
     SUMMARY OF INVENTION 
     Technical Problem 
       [0005]    However, according to Patent Literature 1, a matching circuit of a receiving system is arranged before a filter and a signal after impedance conversion by the matching circuit is inputted to the filter, which results in a problem that it is not possible to independently design each matching circuit. That is, according to Patent Literature 1, if a constant of each matching circuit is changed, optimum constants of other matching circuits are also changed, and it is necessary to consider influences from the other matching circuits when designing each matching circuit. Furthermore, according to Patent Literature 1, it is necessary to perform frequency tuning using a duplexer to handle a plurality of frequencies, which results in a problem that the circuit scale increases, and hence an increase in manufacturing cost. 
         [0006]    The present invention has been implemented in view of such problems and it is therefore an object of the present invention to provide a portable radio apparatus capable of independently designing each matching circuit, suppressing increases in the circuit scale and reducing manufacturing cost. 
       Solution to Problem 
       [0007]    A portable radio apparatus according to the present invention adopts a configuration including an antenna, a first suppressing section that suppresses a first frequency band of a signal received through the antenna, a second suppressing section that suppress a second frequency band of the signal received through the antenna, a first radio section that demodulates the signal of the suppressed first frequency band and acquires data superimposed on the signal of the second frequency band, a second radio section that demodulates the signal of the suppressed second frequency band and acquires data superimposed on the signal of the first frequency band, a first matching circuit connected between the first suppressing section and the first radio section to provide impedance matching between the first suppressing section and the first radio section, and a second matching circuit connected between the second suppressing section and the second radio section to provide impedance matching between the second suppressing section and the second radio section. 
       Advantageous Effects of Invention 
       [0008]    According to the present invention, it is possible to independently design each matching circuit, suppress increases in the circuit scale and reduce manufacturing cost. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0009]      FIG. 1  is a block diagram illustrating a configuration of a portable radio apparatus according to Embodiment 1 of the present invention; 
           [0010]      FIG. 2  is a diagram illustrating band-pass characteristics of a filter according to Embodiment 1 of the present invention; 
           [0011]      FIG. 3  is a diagram illustrating band-pass characteristics of a filter according to Embodiment 1 of the present invention; 
           [0012]      FIG. 4  is a diagram illustrating an operation of conversion to a characteristic impedance through a matching circuit according to Embodiment 1 of the present invention; 
           [0013]      FIG. 5  is a diagram illustrating an operation of conversion to a complex conjugate impedance through the matching circuit according to Embodiment 1 of the present invention; 
           [0014]      FIG. 6  is a block diagram illustrating a configuration of a portable radio apparatus according to Embodiment 2 of the present invention; 
           [0015]      FIG. 7  is a diagram illustrating an impedance at an output of an antenna element according to Embodiment 2 of the present invention; 
           [0016]      FIG. 8  is a diagram illustrating an impedance at an output of a filter according to Embodiment 2 of the present invention; 
           [0017]      FIG. 9  is a diagram illustrating an impedance at an output of a matching circuit according to Embodiment 2 of the present invention; 
           [0018]      FIG. 10  is a diagram illustrating an impedance at an output of the antenna element according to Embodiment 2 of the present invention; 
           [0019]      FIG. 11  is a diagram illustrating an impedance at an output of the filter according to Embodiment 2 of the present invention; 
           [0020]      FIG. 12  is a diagram illustrating an impedance at an output of the matching circuit according to Embodiment 2 of the present invention; 
           [0021]      FIG. 13  is a diagram illustrating an impedance at an output of an amplifier according to Embodiment 2 of the present invention; 
           [0022]      FIG. 14  is a block diagram illustrating a configuration of a portable radio apparatus according to Embodiment 3 of the present invention; 
           [0023]      FIG. 15  is a block diagram illustrating a configuration of a portable radio apparatus according to Embodiment 4 of the present invention; and 
           [0024]      FIG. 16  is a block diagram illustrating a configuration of a portable radio apparatus according to Embodiment 5 of the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0025]    Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
       Embodiment 1 
       [0026]      FIG. 1  is a block diagram illustrating a configuration of portable radio apparatus  100  according to Embodiment 1 of the present invention. 
         [0027]    Portable radio apparatus  100  is mainly comprised of antenna  101 , filter  102 , matching circuit  103 , radio section  104 , filter  105 , matching circuit  106  and radio section  107 . 
         [0028]    Furthermore, in portable radio apparatus  100 , a sequence (hereinafter referred to as “first sequence”) made up of antenna  101 , filter  102 , matching circuit  103  and radio section  104  performs both transmission processing of superimposing data on a signal of frequency f 1  and reception processing of acquiring data superimposed on a signal of frequency f 1 . Furthermore, in portable radio apparatus  100 , a sequence (hereinafter referred to as “second sequence”) made up of antenna  101 , filter  105 , matching circuit  106  and radio section  107  performs only reception processing of acquiring data superimposed on a signal of frequency f 2  to frequency f 3 . 
         [0029]    Here, the data superimposed on the signal processed in the first sequence is, for example, data of Bluetooth (registered trademark) and the data superimposed on the signal processed in the second sequence is, for example, data of digital television. 
         [0030]    Hereinafter, the components of portable radio apparatus  100  will be described in detail. 
         [0031]    Antenna  101  functions as a mono-pole antenna and has an antenna element having an electrical length of ¼ wavelength or less. Antenna  101  receives a signal of radio system  1  using frequency f 1  and a signal of radio system  2  using a signal of frequency f 2  to frequency f 3  and outputs each received signal to filter  102  and filter  105 . Furthermore, antenna  101  transmits a signal of radio system  1  using frequency f 1  inputted from filter  102 . Here, radio system  2  has a wider band than radio system  1 . Furthermore, frequency f 1  is, for example, 2450 MHz. On the other hand, frequency f 2  is, for example, 475 MHz. Frequency f 3  is, for example, 650 MHz. 
         [0032]    Filter  102  is, for example, a band elimination filter (BEF) which suppresses frequency f 2  to frequency f 3  of the signal inputted from antenna  101  and outputs the signal of suppressed frequency f 2  to frequency f 3  to matching circuit  103 . Furthermore, filter  102  suppresses frequency f 2  to frequency f 3  of the signal inputted from matching circuit  103  and outputs the signal of suppressed frequency f 2  to frequency f 3  to antenna  101 . That is, filter  102  suppresses frequency f 2  to frequency f 3  used in radio system  2  processed in the second sequence other than radio system  1  processed in the first sequence. For filter  102 , it is preferable to use a filter with the lowest possible pass loss of frequency f 1 . 
         [0033]    Matching circuit  103  is connected in series between filter  102  and radio section  104  which will be described later and realizes impedance matching between filter  102  and radio section  104 . To be more specific, matching circuit  103  converts an impedance of the signal inputted from filter  102  to characteristic impedance An. 
         [0034]    Radio section  104  demodulates the signal inputted from matching circuit  103  and acquires data superimposed on frequency f 1 . 
         [0035]    Furthermore, radio section  104  performs modulation of superimposing data on frequency f 1  and outputs the modulated signal to matching circuit  103 . 
         [0036]    Filter  105  is, for example, a band elimination filter (BEF) which suppresses frequency f 1  of the signal inputted from antenna  101  and outputs the signal of suppressed frequency f 1  to matching circuit  106 . That is, filter  105  suppresses frequency f 1  used in radio system  1  processed in the first sequence other than radio system  2  processed in the second sequence. For filter  105 , it is preferable to use a filter with the lowest possible pass loss of frequency f 2  to frequency f 3 . 
         [0037]    Matching circuit  106  is connected in series between filter  105  and radio section  107  which will be described later and realizes impedance matching between filter  105  and radio section  107 . To be more specific, matching circuit  106  converts the impedance of the signal inputted from filter  105  so that an output impedance of matching circuit  106  and an input impedance of radio section  107  have a complex conjugate relationship and outputs the signal to radio section  107 . 
         [0038]    Radio section  107  demodulates the signal inputted from matching circuit  106  and acquires data superimposed on frequency f 2  to frequency f 3 . 
         [0039]      FIG. 2  is a diagram illustrating band-pass characteristics of filter  102  and  FIG. 3  is a diagram illustrating band-pass characteristics of filter  105 . 
         [0040]    Next, operations of matching circuit  103  and matching circuit  106  will be described. 
         [0041]      FIG. 4  is a diagram illustrating an operation of conversion to a characteristic impedance through matching circuit  103 . 
         [0042]    As shown in  FIG. 4 , when, for example, the impedance of radio section  104  is Z=50±j0Ω, when matching the impedance at the output of matching circuit  103 , impedance conversion is performed so as to obtain impedance Z=50±j0Ω. As a result, after matching circuit  103  performs impedance conversion to characteristic impedance An, a point on a Smith chart is plotted at the position of f 1  which is the center of the Smith chart. 
         [0043]      FIG. 5  is a diagram illustrating an operation of conversion to a complex conjugate impedance through matching circuit  106 . 
         [0044]    As shown in  FIG. 5 , if the input impedance of radio section  107  is, for example, Z 2 =A−jB Ω at a predetermined frequency, when matching circuit  106  performs matching of the output impedance, matching circuit  106  performs impedance conversion so that output impedance Z 1  becomes Z 1 =A+jB Ω. After converting impedance so that output impedance Z 1  of matching circuit  106  and input impedance Z 2  of radio section  107  have a complex conjugate relationship, points on the Smith chart are plotted at positions of f 2   a  and f 2   b  for frequency f 2  and plotted at positions of f 3   a  and f 3   b  for frequency f 3 . Plotted f 2   a  and f 2   b  are plotted at positions symmetric with respect to horizontal axis # 503 . Likewise, plotted f 3   a  and f 3   b  are plotted at positions symmetric with respect to horizontal axis # 503 . 
         [0045]    Receiving a signal of wide band radio system  2  of 475 MHz to 650 MHz generally requires an antenna element having a length of 16 cm to 12 cm which is ¼ wavelength. However, according to the present embodiment, matching circuit  106  performs impedance conversion of the signal inputted from filter  105  so that the output impedance of matching circuit  106  and the input impedance of radio section  107  have a complex conjugate relationship in wide band radio system  2  of 475 MHz to 650 MHz. In the present embodiment, this eliminates the necessity of obtaining a characteristic impedance which has a constant value over an entire desired band using an antenna element alone, and it is thereby possible to receive a signal of radio system  2  through antenna  101  with an antenna element having a length of approximately 5 cm. 
         [0046]    Thus, the present embodiment provides a filter that suppresses a frequency used in another radio system between the matching circuit and the antenna, and thereby prevents, when simultaneously transmitting or receiving signals of a plurality of different radio systems, the matching circuit of each radio system from receiving influences of impedance of the other radio system, and can independently design each matching circuit, suppress increases in the circuit scale and reduce manufacturing cost. Furthermore, the present embodiment converts a signal of a wide band radio system to a complex conjugate impedance, and can thereby receive a signal of a wide band radio system through an antenna element of a smaller electrical length than a normal length and thus reduce the size and thickness of the housing when accommodating the antenna elements in the housing. 
       Embodiment 2 
       [0047]      FIG. 6  is a block diagram illustrating a configuration of portable radio apparatus  600  according to Embodiment 2 of the present invention. 
         [0048]    Portable radio apparatus  600  shown in  FIG. 6  adds amplifier  601  to portable radio apparatus  100  according to Embodiment 1 shown in  FIG. 1 . In  FIG. 6 , the same components as those in  FIG. 1  will be assigned the same reference numerals and descriptions thereof will be omitted. 
         [0049]    Portable radio apparatus  600  is mainly comprised of antenna  101 , filter  102 , matching circuit  103 , radio section  104 , filter  105 , matching circuit  106 , amplifier  601  and radio section  107 . 
         [0050]    Furthermore, a sequence made up of antenna  101 , filter  105 , matching circuit  106 , amplifier  601  and radio section  107  in portable radio apparatus  600  performs only reception processing of acquiring data superimposed on a signal of frequency f 2  to frequency f 3 . 
         [0051]    Matching circuit  106  is connected in series between filter  105  and amplifier  601  which will be described later to provide impedance matching between filter  105  and amplifier  601 . To be more specific, matching circuit  106  converts the impedance of a signal inputted from filter  105  so that the impedance of the signal inputted from filter  105  and the input impedance of radio section  107  have a complex conjugate relationship and outputs the converted impedance to amplifier  601 . 
         [0052]    Amplifier  601  amplifies the signal inputted from matching circuit  106  and outputs the amplified signal to radio section  107 . In this case, for amplifier  601 , the input impedance is impedance of a complex number and the output impedance is characteristic impedance BΩ. Furthermore, amplifier  601  has a gain of 0 dB or more at frequency f 2  to frequency f 3  and it is preferable to use an amplifier having the highest possible gain at frequency f 2  to frequency f 3  and having a low noise factor (NF) as well. 
         [0053]    Radio section  107  demodulates the signal inputted from amplifier  601  and acquires data superimposed on frequency f 2  to frequency f 3 . 
         [0054]      FIG. 7  to  FIG. 9  are diagrams illustrating an impedance variation in the first sequence on a Smith chart and  FIG. 10  to  FIG. 13  are diagrams illustrating an impedance variation in the second sequence on a Smith chart. 
         [0055]      FIG. 7  is a diagram illustrating an impedance at the output of antenna  101 ,  FIG. 8  is a diagram illustrating an impedance at the output of filter  102  and  FIG. 9  is a diagram illustrating an impedance at the output of matching circuit  103 . 
         [0056]    Furthermore,  FIG. 10  is a diagram illustrating an impedance at the output of antenna  101 ,  FIG. 11  is a diagram illustrating an impedance at the output of filter  105 ,  FIG. 12  is a diagram illustrating an impedance at the output of matching circuit  106  and  FIG. 13  is a diagram illustrating an impedance at the input of amplifier  601 . 
         [0057]    In  FIG. 7 , ml corresponds to frequency=2.450 GHz and impedance=10.993+j22.494Ω. Furthermore, in  FIG. 8 , ml corresponds to frequency=2.450 GHz and impedance=36.954-j35.859Ω. Furthermore, in  FIG. 9 , ml corresponds to frequency=2.450 GHz and impedance=49.982+j0.104Ω. 
         [0058]    Furthermore, in  FIG. 10 , ml corresponds to frequency 475.0 MHz and impedance=5.815-j70.250Ω, and m 2  corresponds to frequency=650.0 MHz and impedance=3.708-j35.137Ω. In  FIG. 11 , m 1  corresponds to frequency=475.0 MHz and impedance=2.873+j51.631Ω, and m 2  corresponds to frequency=650.0 MHz and impedance=335.853+j19.710Ω. On the other hand, in  FIG. 12 , m 1  corresponds to frequency=475.0 MHz and impedance=788.899-j40.139Ω, and m 2  corresponds to frequency=650.0 MHz and impedance=20.671+j78.636Ω. In  FIG. 13 , m 1  corresponds to frequency=475.0 MHz and impedance=336.234-j14.243Ω, and m 2  corresponds to frequency=650.0 MHz and impedance=29.228-j71.516Ω. 
         [0059]    The present embodiment processes a signal of a radio system that performs transmission in the first sequence and processes a signal of a radio system that performs only reception and a signal of a radio system that uses a band within the band of amplifier  601  in the second sequence. 
         [0060]    Thus, the present embodiment provides a filter that suppresses a frequency used in another radio system between a matching circuit and an antenna, a matching circuit of each radio system is not affected by an impedance of the other radio system when simultaneously receiving signals of a plurality of different radio systems, and it is thereby possible to independently design each matching circuit, suppress increases in the circuit scale and reduce manufacturing cost. Furthermore, the present embodiment converts a signal of a wide band radio system to a complex conjugate impedance, thus enables a signal of the wide band radio system to be received with an antenna element having a smaller electrical length than a normal length, and can thereby reduce, when accommodating the antenna element in a housing, the size and thickness of the housing. 
       Embodiment 3 
       [0061]      FIG. 14  is a block diagram illustrating a configuration of portable radio apparatus  1400  according to Embodiment 3 of the present invention. 
         [0062]    Portable radio apparatus  1400  is mainly comprised of antenna  1401 , filter  1402 , matching circuit  1403 , radio section  1404 , filter  1405 , matching circuit  1406 , radio section  1407 , filter  1408 , matching circuit  1409 , amplifier  1410  and radio section  1411 . 
         [0063]    In portable radio apparatus  1400 , a sequence (hereinafter referred to as “third sequence”) made up of antenna  1401 , filter  1402 , matching circuit  1403  and radio section  1404  performs both transmission processing of superimposing data on a signal of frequency f 11  and reception processing of acquiring data superimposed on a signal of frequency f 11 . On the other hand, in portable radio apparatus  1400 , a sequence (hereinafter referred to as “fourth sequence”) made up of antenna  1401 , filter  1405 , matching circuit  1406 , radio section  1407  performs both transmission processing of superimposing data on a signal of frequency f 12  and reception processing of acquiring data superimposed on a signal of frequency f 12 . In portable radio apparatus  1400 , a sequence (hereinafter referred to as “fifth sequence”) made up of antenna  1401 , filter  1408 , matching circuit  1409 , amplifier  1410  and radio section  1411  performs only reception processing of acquiring data superimposed on a signal of frequency f 13  to frequency f 14 . 
         [0064]    Hereinafter, the components of portable radio apparatus  1400  will be described. 
         [0065]    Antenna  1401  functions, for example, as a mono-pole antenna and includes an antenna element having an electrical length of ¼ wavelength or less. Antenna  1401  receives a signal of radio system  11  using frequency f 11 , a signal of radio system  12  using frequency f 12  and a signal of radio system  13  using frequency f 13  to frequency f 14  and outputs each received signal to filter  1402 , filter  1405  and filter  1408 . Furthermore, antenna  1401  transmits the signal of radio system  11  using frequency f 11  inputted from filter  1402  or the signal of radio system  12  using frequency f 12  inputted from filter  1405 . Here, radio system  13  has a wider band than radio system  11  and radio system  12 . 
         [0066]    Filter  1402  is, for example, a band elimination filter (BEF) which suppresses frequency f 12 , and frequency f 13  to frequency f 14  of a signal inputted from antenna  1401  and outputs the signal of suppressed frequency f 12 , and frequency f 13  to frequency f 14  to matching circuit  1403 . Furthermore, filter  1402  suppresses frequency f 12 , and frequency f 13  to frequency f 14  of a signal inputted from matching circuit  1403  and outputs the signal of suppressed frequency f 12 , and frequency f 13  to frequency f 14  to antenna  1401 . That is, filter  1402  suppresses frequency f 12  used in radio system  12  processed in the fourth sequence and frequency f 13  to frequency f 14  used in radio system  13  processed in the fifth sequence other than radio system  11  processed in the third sequence other than radio system  11  processed in the third sequence. For filter  1402 , it is preferable to use a filter with the lowest possible pass loss of frequency f 11 . 
         [0067]    Matching circuit  1403  is connected in series between filter  1402  and radio section  1404  which will be described later to provide impedance matching between filter  1402  and radio section  1404 . To be more specific, matching circuit  1403  converts an impedance of the signal inputted from filter  1402  to characteristic impedance CΩ. 
         [0068]    Radio section  1404  demodulates the signal inputted from matching circuit  1403  and acquires data superimposed on frequency f 11 . Furthermore, radio section  1404  performs modulation of superimposing data on frequency f 1   1  and outputs the modulated signal to matching circuit  1403 . 
         [0069]    Filter  1405  is, for example, a band elimination filter (BEF) which suppresses frequency f 11  and frequency f 13  to frequency f 14  of a signal inputted from antenna  1401  and outputs the signal of suppressed frequency f 11 , and frequency f 13  to frequency f 14  to matching circuit  1406 . Furthermore, filter  1405  suppresses frequency f 11  and frequency f 13  to frequency f 14  of the signal inputted from matching circuit  1406  and outputs the signal of suppressed frequency f 11 , and frequency f 13  to frequency f 14  to antenna  1401 . That is, filter  1405  suppresses frequency f 11  used in radio system  11  processed in the third sequence and frequency f 13  to frequency f 14  used in radio system  13  processed in the fifth sequence other than radio system  12  processed in the fourth sequence. For filter  1405 , it is preferable to use a filter with the lowest possible pass loss of frequency f 12 . 
         [0070]    Matching circuit  1406  is connected in series between filter  1405  and radio section  1407  which will be described later to provide impedance matching between filter  1405  and radio section  1407 . To be more specific, matching circuit  1406  converts an impedance of the signal inputted from filter  1405  to characteristic impedance Dn. 
         [0071]    Radio section  1407  demodulates the signal inputted from matching circuit  1406  and acquires data superimposed on frequency f 12 . Furthermore, radio section  1407  performs modulation of superimposing data on frequency f 12  and outputs the modulated signal to matching circuit  1406 . 
         [0072]    Filter  1408  is, for example, a band elimination filter (BEF) which suppresses frequency f 11  and frequency f 12  of a signal inputted from antenna  1401  and outputs the signal of suppressed frequency f 11  and frequency f 12  to matching circuit  1409 . That is, filter  1408  suppresses frequency f 11  used in radio system  11  processed in the third sequence and frequency f 12  used in radio system  12  processed in the fourth sequence other than radio system  13  processed in the fifth sequence. For filter  1408 , it is preferable to use a filter with the lowest possible pass loss of frequency f 13  to frequency f 14 . 
         [0073]    Matching circuit  1409  is connected in series between filter  1408  and amplifier  1410  which will be described later to provide impedance matching between filter  1408  and amplifier  1410 . To be more specific, matching circuit  1409  converts an impedance of the signal inputted from filter  1408  so that the output impedance of matching circuit  1409  and the input impedance of amplifier  1410  have a complex conjugate relationship and outputs the converted impedance to amplifier  1410 . 
         [0074]    Amplifier  1410  amplifies the signal inputted from matching circuit  1409  and outputs the amplified signal to radio section  1411 . In this case, the input impedance of amplifier  1410  and the output impedance of matching circuit  1409  have a complex conjugate relationship and the output impedance of amplifier  1410  is characteristic impedance EΩ. Furthermore, for amplifier  1410 , it is preferable to use an amplifier having a gain of 0 dB or more at frequency f 13  to frequency f 14 , having the highest possible gain at frequency f 13  to frequency f 14  and having a low noise factor (NF) as well. 
         [0075]    Radio section  1411  demodulates the signal inputted from amplifier  1410  and acquires data superimposed on frequency f 13  to frequency f 14 . 
         [0076]    In the present embodiment, a signal of a radio system that performs transmission is processed in the third sequence or fourth sequence, and a signal of a radio system that performs only reception and a signal of a radio system using a band within the band of amplifier  1410  are processed in the fifth sequence. 
         [0077]    Thus, according to the present embodiment, effects similar to those of Embodiment 1 can be obtained with the portable radio apparatus made up of three processing sequences; the third sequence and fourth sequence performing transmission/reception processing and the fifth sequence performing only reception processing. Furthermore, the present embodiment uses an amplifier having the highest possible gain in the reception band and having a low noise factor (NF) as well, thereby suppresses increases in noise as much as possible, and can thereby amplify a desired received signal and improve reception sensitivity. 
         [0078]    In the present embodiment, although the signal of radio system  13  is amplified by the amplifier, the present invention is not limited to this but the amplifier may be removed. 
       Embodiment 4 
       [0079]      FIG. 15  is a block diagram illustrating a configuration of portable radio apparatus  1500  according to Embodiment  4  of the present invention. 
         [0080]    Portable radio apparatus  1500  is mainly comprised of antenna  1501 , filter  1502 , matching circuit  1503 , radio section  1504 , filter  1505 , matching circuit  1506 , amplifier  1507 , radio section  1508 , filter  1509 , matching circuit  1510 , amplifier  1511  and radio section  1512 . 
         [0081]    Furthermore, in portable radio apparatus  1500 , a sequence (hereinafter referred to as “sixth sequence”) made up of antenna  1501 , filter  1502 , matching circuit  1503  and radio section  1504  performs both transmission processing of superimposing data on a signal of frequency f 21  and reception processing of acquiring data superimposed on a signal of frequency f 21 . Furthermore, in portable radio apparatus  1500 , a sequence (hereinafter referred to as “seventh sequence”) made up of antenna  1501 , filter  1505 , matching circuit  1506 , amplifier  1507  and radio section  1508  performs only reception processing of acquiring data superimposed on a signal of frequency f 22  to frequency f 23 . Furthermore, in portable radio apparatus  1500 , a sequence (hereinafter referred to as “eighth sequence”) made up of antenna  1501 , filter  1509 , matching circuit  1510 , amplifier  1511  and radio section  1512  performs only reception processing of acquiring data superimposed on a signal of frequency f 24  to frequency f 25 . 
         [0082]    Hereinafter, the components of portable radio apparatus  1500  will be described in detail. 
         [0083]    Antenna  1501  functions, for example, as a mono-pole antenna and has an antenna element having an electrical length of ¼ wavelength or less. Antenna  1501  receives a signal of radio system  21  using frequency f 21 , a signal of radio system  22  using frequency f 22  to frequency f 23  and a signal of radio system  23  using frequency f 24  to frequency f 25 , and outputs each received signal to filter  1502 , filter  1505  and filter  1509 . Furthermore, antenna  1501  transmits a signal of radio system  21  using frequency f 21  inputted from filter  1502 . Here, radio system  22  and radio system  23  have a wider band than radio system  21 . 
         [0084]    Filter  1502  is, for example, a band elimination filter (BEF) which suppresses frequency f 22  to frequency f 23  and frequency f 24  to frequency f 25  of the signal inputted from antenna  1501  and outputs the signal of suppressed frequency f 22  to frequency f 23  and frequency f 24  to frequency f 25  to matching circuit  1503 . Furthermore, filter  1502  suppresses frequency f 22  to frequency f 23  and frequency f 24  to frequency f 25  of the signal inputted from matching circuit  1503  and outputs the signal of suppressed frequency f 22  to frequency f 23  and frequency f 24  to frequency f 25  to antenna  1501 . That is, filter  1502  suppresses frequency f 22  to frequency f 23  used in radio system  22  processed in the seventh sequence and frequency f 24  to frequency f 25  used in radio system  23  processed in the eighth sequence other than radio system  21  processed in the sixth sequence. For filter  1502 , it is preferable to use a filter with the lowest possible pass loss of frequency f 21 . 
         [0085]    Matching circuit  1503  is connected in series between filter  1502  and radio section  1504  which will be described later to provide impedance matching between filter  1502  and radio section  1504 . To be more specific, matching circuit  1503  converts an impedance of the signal inputted from filter  1502  to characteristic impedance Fn. 
         [0086]    Radio section  1504  demodulates the signal inputted from matching circuit  1503  and acquires data superimposed on frequency f 21 . Furthermore, radio section  1504  performs modulation of superimposing data on frequency f 21  and outputs the modulated signal to matching circuit  1503 . 
         [0087]    Filter  1505  is, for example, a band elimination filter (BEF) which suppresses frequency f 21  and frequency f 24  to frequency f 25 , and outputs the signal of suppressed frequency f 21  and frequency f 24  to frequency f 25  to matching circuit  1506 . That is, filter  1505  suppresses frequency f 21  used in radio system  21  processed in the sixth sequence and frequency f 24  to frequency f 25  used in radio system  23  processed in the eighth sequence other than radio system  22  processed in the seventh sequence. For filter  1505 , it is preferable to use a filter with the lowest possible pass loss of frequency f 22  to frequency f 23 . 
         [0088]    Matching circuit  1506  is connected in series between filter  1505  and amplifier  1507  which will be described later to provide impedance matching between filter  1505  and amplifier  1507 . To be more specific, matching circuit  1506  converts an impedance of the signal inputted from filter  1505  so that the output impedance of matching circuit  1506  and the input impedance of amplifier  1507  have a complex conjugate relationship and outputs the converted impedance to amplifier  1507 . 
         [0089]    Amplifier  1507  amplifies the signal inputted from matching circuit  1506  and outputs the amplified signal to radio section  1508 . In this case, the input impedance of amplifier  1507  and the output impedance of matching circuit  1506  have a complex conjugate relationship and the output impedance of amplifier  1507  is characteristic impedance G. Furthermore, amplifier  1507  has a gain of 0 dB or more at frequency f 22  to frequency f 23  and it is preferable to use an amplifier having the highest possible gain at frequency f 22  to frequency f 23  and having a low noise factor (NF) as well. 
         [0090]    Radio section  1508  demodulates the signal inputted from amplifier  1507  and acquires data superimposed on frequency f 22  to frequency f 23 . 
         [0091]    Filter  1509  is, for example, a band elimination filter (BEF) which suppresses frequency f 21  and frequency f 22  to frequency f 23  of the signal inputted from antenna  1501  and outputs the signal of suppressed frequency f 21  and frequency f 22  to frequency f 23  to matching circuit  1510 . That is, filter  1509  suppresses frequency f 21  used in radio system  21  processed in the sixth sequence and frequency f 22  to frequency f 23  used in radio system  22  processed in the seventh sequence other than radio system  23  processed in the eighth sequence. For filter  1509 , it is preferable to use a filter with the lowest possible pass loss of frequency f 24  to frequency f 25 . 
         [0092]    Matching circuit  1510  is connected in series between filter  1509  and amplifier  1511  which will be described later to provide impedance matching between filter  1509  and amplifier  1511 . To be more specific, matching circuit  1510  converts an impedance of the signal inputted from filter  1509  so that the output impedance of matching circuit  1510  and the input impedance of amplifier  1511  have a complex conjugate relationship and outputs the converted impedance to amplifier  1511 . 
         [0093]    Amplifier  1511  amplifies the signal inputted from matching circuit  1510  and outputs the amplified signal to radio section  1512 . In this case, the input impedance of amplifier  1511  and the output impedance of matching circuit  1510  have a complex conjugate relationship and the output impedance of amplifier  1511  is characteristic impedance H. Furthermore, amplifier  1511  has a gain of 0 dB or more at frequency f 24  to frequency f 25  and it is preferable to use an amplifier having the highest possible gain at frequency f 24  to frequency f 25  and having a low noise factor (NF) as well. 
         [0094]    Radio section  1512  demodulates the signal inputted from amplifier  1511  and acquires data superimposed on frequency f 24  to frequency f 25 . 
         [0095]    The present embodiment processes a signal of a radio system that performs transmission in the sixth sequence, processes a signal of a radio system that performs only reception and a signal of a radio system that uses a band within the band of amplifier  1507  in the seventh sequence and processes a signal of a radio system that performs only reception and a signal of a radio system that uses a band within the band of amplifier  1511  in the eighth sequence. 
         [0096]    As described so far, according to the present embodiment, effects similar to those in Embodiment 1 can be obtained with the portable radio apparatus made up of three processing sequences; sixth sequence that performs transmission/reception processing, seventh sequence and eighth sequence that perform only reception processing. Furthermore, the present embodiment uses an amplifier having the highest possible gain and a low noise factor (NF) for a reception band as well, can thereby suppress increases of noise as much as possible, amplify a desired received signal and improve reception sensitivity. 
         [0097]    In the present embodiment, although the signals of radio system  22  and radio system  23  are amplified by an amplifier, the present embodiment is not limited to this but one or both of the amplifiers of radio system  22  and radio system  23  may be removed. 
       Embodiment 5 
       [0098]      FIG. 16  is a block diagram illustrating a configuration of portable radio apparatus  1600  according to Embodiment 5 of the present invention. 
         [0099]    Portable radio apparatus  1600  is mainly comprised of antenna  1601 , filter  1602 , matching circuit  1603 , radio section  1604 , filter  1605 , matching circuit  1606 , amplifier  1607 , radio section  1608  and radio section  1609 . 
         [0100]    Furthermore, a sequence (hereinafter referred to as “ninth sequence”) made up of antenna  1601 , filter  1602 , matching circuit  1603  and radio section  1604  in portable radio apparatus  1600  performs both transmission processing of superimposing data on a signal of frequency f 31  and reception processing of acquiring data superimposed on a signal of frequency f 31 . Furthermore, a sequence (hereinafter referred to as “tenth sequence”) made up of antenna  1601 , filter  1605 , matching circuit  1606 , amplifier  1607  and radio section  1608  in portable radio apparatus  1600  performs only reception processing of acquiring data superimposed on a signal of frequency f 32  to frequency f 33 . Furthermore, a sequence (hereinafter referred to as “eleventh sequence”) made up of antenna  1601 , filter  1605 , matching circuit  1606 , amplifier  1607  and radio section  1609  in portable radio apparatus  1600  performs only reception processing of acquiring data superimposed on a signal of frequency f 34  to frequency f 35 . 
         [0101]    Hereinafter, the components of portable radio apparatus  1600  will be described in detail. 
         [0102]    Antenna  1601  functions, for example, as a mono-pole antenna and includes an antenna element having an electrical length of ¼ wavelength or less. Antenna  1601  receives a signal of radio system  31  using frequency f 31 , a signal of radio system  32  using frequency f 32  to frequency f 33  and a signal of radio system  33  using frequency f 34  to frequency f 35  and outputs each received signal to filter  1602  and filter  1605 . Furthermore, antenna  1601  transmits the signal of radio system  31  using frequency f 31  inputted from filter  1602 . Here, radio system  32  and radio system  33  have a wider band than radio system  31 . 
         [0103]    Filter  1602  is, for example, a band elimination filter (BEF) which suppresses frequency f 32  to frequency f 35  of a signal inputted from antenna  1601  and outputs the signal of suppressed frequency f 32  to frequency f 35  to matching circuit  1603 . Furthermore, filter  1602  suppresses frequency f 32  to frequency f 35  of a signal inputted from matching circuit  1603  and outputs the signal of suppressed frequency f 32  to frequency f 35  to antenna  1601 . That is, filter  1602  suppresses frequency f 32  to frequency f 33  used in radio system  32  processed in the tenth sequence and frequency f 34  to frequency f 35  used in radio system  33  processed in the eleventh sequence other than radio system  31  processed in the ninth sequence. For filter  1602 , it is preferable to use a filter with the lowest possible pass loss of frequency f 31 . 
         [0104]    Matching circuit  1603  is connected in series between filter  1602  and radio section  1604  which will be described later to provide impedance matching between filter  1602  and radio section  1604 . To be more specific, matching circuit  1603  converts an impedance of the signal inputted from filter  1602  to characteristic impedance In. 
         [0105]    Radio section  1604  demodulates the signal inputted from matching circuit  1603  and acquires data superimposed on frequency f 31 . Furthermore, radio section  1604  performs modulation of superimposing data on frequency f 31  and outputs the modulated signal to matching circuit  1603 . 
         [0106]    Filter  1605  is, for example, a band elimination filter (BEF) which suppresses frequency f 31  of a signal inputted from antenna  1601  and outputs the signal of suppressed frequency f 31  to matching circuit  1606 . That is, filter  1605  suppresses frequency f 31  used in radio system  31  processed in the eleventh sequence other than radio system  32  and radio system  33  processed in the tenth sequence and eleventh sequence. For filter  1605 , it is preferable to use a filter with the lowest possible pass loss of frequency f 32  to frequency f 35 . 
         [0107]    Matching circuit  1606  is connected in series between filter  1605  and amplifier  1607  which will be described later to provide impedance matching between filter  1605  and amplifier  1607 . To be more specific, matching circuit  1606  converts an impedance of the signal inputted from filter  1605  so that the output impedance of matching circuit  1606  and the input impedance of amplifier  1607  have a complex conjugate relationship and outputs the converted impedance to amplifier  1607 . 
         [0108]    Amplifier  1607  amplifies the signal inputted from matching circuit  1606  and outputs the amplified signal to radio section  1608  and radio section  1609 . In this case, the input impedance of amplifier  1607  and the output impedance of matching circuit  1606  have a complex conjugate relationship and the output impedance of amplifier  1607  is characteristic impedance J. Furthermore, for amplifier  1607 , it is preferable to use an amplifier having a gain of 0 dB or more at frequency f 32  to frequency f 35 , having the highest possible gain at frequency f 32  to frequency f 35  and having a low noise factor (NF) as well. 
         [0109]    Radio section  1608  demodulates the signal inputted from amplifier  1607  and acquires data superimposed on frequency f 32  to frequency f 33 . 
         [0110]    Radio section  1609  demodulates the signal inputted from amplifier  1607  and acquires data superimposed on frequency f 34  to frequency f 35 . 
         [0111]    In the present embodiment, a signal of a radio system that performs transmission is processed in the ninth sequence, a signal of the radio system that performs only reception and a signal of a radio system that uses a band within the band of amplifier  1607  are processed in the tenth sequence or eleventh sequence. 
         [0112]    Thus, according to the present embodiment, effects similar to those in Embodiment 1 can be obtained with the portable radio apparatus made up of three processing sequences; ninth sequence that performs transmission/reception processing, tenth sequence and eleventh sequence that perform only reception processing and share the amplifier. 
         [0113]    In the present embodiment, although the signal of radio system  32  and the signal of radio system  33  are amplified by the amplifier, the present embodiment is not limited, but the amplifier may be removed. Furthermore, in the present embodiment, although the signal processed in the tenth sequence and the signal processed in the eleventh sequence are set to different frequency bands, the present embodiment is not limited to this, but signals of a radio system using the same or partially overlapping frequency bands may be processed in the tenth sequence and eleventh sequence. 
         [0114]    In above Embodiment 1 to Embodiment 5, although each of signals of a plurality of radio systems is converted to a characteristic impedance and an impedance having a complex conjugate relationship therewith according to the band used, the present invention is not limited to this, but all signals of the plurality of radio systems may be converted to characteristic impedances or all signals of the plurality of radio systems may be converted to impedances having a complex conjugate relationship therewith to connect each circuit. 
         [0115]    In above Embodiment 1 to Embodiment 5, although the sequence of the wide band radio system is used as a receive-only sequence, the present invention is not limited to this, but the sequence of the wide band radio system may be adapted so as to perform processing of both transmission and reception or only transmission. In this case, the amplifier needs to be removed. 
         [0116]    Furthermore, in above Embodiment 1 to Embodiment 5, although a signal of a narrow band radio system and a signal of a wide band radio system are processed respectively, the present invention is not limited to this, but only signals of a plurality of wide band radio systems may be processed or only signals of a plurality of narrow band radio systems may be processed. 
         [0117]    Furthermore, in above Embodiment 1 to Embodiment 5, although processing of both transmission and reception is performed in the processing sequence of a narrow band radio system, the present invention is not limited to this, but one of transmission and reception may be performed. 
         [0118]    The disclosure of Japanese Patent Application No. 2008-280335, filed on Oct. 30, 2008, including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
       INDUSTRIAL APPLICABILITY 
       [0119]    The portable radio apparatus according to the present invention is particularly suitable for use in simultaneously operating a plurality of radio systems by sharing one antenna element.