JP2916513B2 - Cascode type distributed amplifier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a cascode distributed amplifier for amplifying a CHz band high frequency signal.

[Prior art]

2. Description of the Related Art A conventional distributed amplifier described below with reference to FIG. 2 has been proposed. That is, a plurality (n + 1) sequentially connected in series
Number of transmission lines _{LA 1, LA 2 ......... LA n} , have the LA _{(n + 1),} and from one end of the transmission line LA ₁ side together is derived a high frequency signal input terminal 1, the transmission line LA _{( a} first transmission circuit in which the other end on the ( _{n + 1)} side is connected to the ground through a first termination circuit B1 in which a resistance element R1, a capacitance element C1, and a capacitance element C1 (both not shown) are connected in series; Has G1. Further, it has a plurality of (n + 1) transmission lines LB ₁ , LB ₂ ... LB _n , LB _{(n + 1)} sequentially connected in series, and one end on the side of the transmission line LB _{(n + 1)} And the other end of the transmission line LB ₁ side is connected to a resistor R2
And a second transmission circuit G2 connected to ground through a second termination circuit B2 in which the capacitor C2 and a capacitor C2 (both not shown) are connected in series. Furthermore, connected to both a source grounded, and a connection point between the transmission lines LB ₁ and LB ₂ of the drain second transmission circuit G2, the connection midpoint between the LB ₂ and LB ₃ ......... LB _n and LB _{(n + 1)} are connected to connection points, respectively, and gates are further connected to connection points LA ₂ and L ₂ between transmission lines LA ₁ and LA ₂ of the first transmission circuit G1.
A connection midpoint between A ₃ ... A plurality of n field-effect transistors connected respectively to a connection midpoint between LA _n and LA _{(n + 1)}
TA ₁ , TA ₂ ... TA _n . The above is the configuration of a theoretically proposed distributed amplifier. Conventionally, a cascode distributed amplifier described below with reference to FIG. 3 has also been proposed. 3, parts corresponding to those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof will be omitted. The cascode-type distributed amplifier proposed in the prior art shown in FIG. 3 is different from the fundamental distributed amplifier described in FIG. 2 in that a plurality of n transmission lines L connected in series are connected in series.
A third transmission circuit G3 having C ₁ , LC ₂ ... LC _n and extending a bias power supply terminal 3 from one end of the transmission line LC ₁ side, and a plurality of n field effect transistors TB ₁ , TB ₂ ……
… TB _n and field effect transistors TB ₁ , TB
₂ ……… TB _(n-1) , TB _{n use} their transmission lines L
D ₁ , LD ₂ ……… LD _(n-1) and LD _n are respectively connected to the drains of the field effect transistors TA ₁ , TA ₂ ……… TA _(n-1) and TA _n , respectively. The drain is connected to the transmission line LE ₁ , LE ₂ ……
... LE _(n-1), through each of the LE _n, a connection point between the transmission lines LB ₁ and LB ₂ of the second transmission circuit G2, the connection midpoint between the LB ₂ and LB _3, ......... LB Connection point between _(n-1) and LB _n , LB _n and LB
_{(n + 1)} respectively to a connection midpoint connected between a connection midpoint between the connection point, LC ₂ and LC ₃ between the transmission line LC ₁ and LC ₂ of the gate third transmission circuit G3, ...... The field effect transistors TA ₁ and TA ₂ are connected in such a manner that they are connected to the connection midpoint between LC _(n−1) and LC _n and the other end of the third transmission circuit G3 on the transmission line LC _n side, respectively.
......... TA _(n-1), and the drain of the TA _n, a connection point between the transmission lines LB ₁ and LB ₂ of the second transmission circuit G2, the connection midpoint between the LB ₂ and LB _3, ......... Connection midpoint between LB _(n-1) and LB _n , LB _n and LB
It has the same configuration as the principle distributed amplifier described above with reference to FIG. 2, except that it is interposed between the connection middle point between _{(n + 1)} . According to the conventional principle of the distributed amplifier described above with reference to FIG.
By supplying a high-frequency signal of the z range, the high-frequency signal, and transmits the first transmission circuit G1, and a first transmission circuit connected between the transmission lines LA ₁ and LA ₂ of G1 Ki it also bets not a Midpoint, connection midpoint between LA ₂ and LA ₃ ... High-frequency signal components obtained at the connection midpoint between LA _n and LA _{(n + 1)} are field-effect transistors TA ₁ and TA ₂ , respectively. Each amplified by TA _n , then the amplified high frequency signal components are:
Connection point between the transmission lines LB ₁ and LB ₂ of the second transmission circuit G2,
A connection midpoint between LB ₂ and LB ₃ is supplied to the second transmission circuit G2 through a connection midpoint between LB _n and LB _{(n + 1)} , respectively.
Therefore, the high frequency signal supplied to the high frequency signal input terminal 1 is amplified by the field effect transistor TA ₁ to Ta _n, is output to the high-frequency signal output terminal 2. Then, in this case, the transmission line LA _{1 of} the first transmission circuit G1
Connection midpoint between and LA _2, a connection point between LA ₂ and LA ₃ ......... L
It has a distributed capacitance between each of the connection midpoints between A _n and LA _{(n + 1)} and ground, so that the first transmission circuit G1 is configured in a distributed manner and the second transmission circuit G2 transmission lines LB ₁ and L
Connection point between the B _2, also between the respective ground connection midpoint between the connection midpoint ......... LB _n and LB _{(n + 1)} between LB ₂ and LB ₃ has a volume of distribution, Therefore, the second transmission circuit G2 is also configured in a distributed manner. From the above, according to the conventional principle of the distributed amplifier described above with reference to FIG. 2, although the detailed description is omitted, it has a wideband amplification characteristic. Further, according to the conventional cascode type distributed amplifier shown in FIG. 3, have the same configuration as a conventional distributed amplifier described above in Figure 2, except the matters described above, the field effect transistor TA ₁ and TB ₁ , TA ₂ and TB ₂ ... TA _n and TB _n are connected in a cascode form, respectively. Therefore, detailed description is omitted, but the transmission lines LB ₁ and LB _{2 of} the second transmission circuit G2 are omitted.
Connection point between the connection midpoint between the LB ₂ and LB ₃ ......... LB _n and L
From the connection midpoint between B _{(n + 1), the} field-effect transistors TA ₁ and TA ₂
... The output impedance on the TA _n side is higher than that of the conventional principle of the distributed amplifier described above with reference to FIG. 2, and therefore, the transmission lines LA ₁ and L 1 of the first transmission circuit G1.
The high-frequency signal components obtained at the connection midpoint between A ₂ and the connection midpoint between LA ₂ and LA ₃ , respectively, are described above with reference to FIG. 2 at the connection midpoint between LA _n and LA _{(n + 1)} . compared to the conventional distributed amplifier amplifies each of higher power, a connection point between the transmission lines LB ₁ and LB ₂ of the second transmission circuit G2, the connection midpoint between the LB ₂ and LB ₃ ...... ... it is possible to output to the connection point between LB _n and LB _{(n + 1),} a connection point between the transmission lines LA ₁ and LA ₂ of the first transmission circuit G1, between LA ₂ and LA ₃ connection point ......... LA _n and LA _{(n + 1)} the high frequency signal components obtained respectively connection point between the connection midpoint between the transmission lines LB ₁ and LB ₂ of the second transmission circuit G2 of, Connection midpoint between LB ₂ and LB ₃ …… LB _n
And LB _{(n + 1)} may leak to the connection midpoint, respectively.
Since it is much lower than that of the conventional distributed amplifier described above with reference to FIG. 2, it has better broadband amplification characteristics than the conventional distributed amplifier described above with reference to FIG.

[Problems to be solved by the invention]

However, in the case of FIG. 3 in the conventional cascode type distributed amplifier described above, the transmission line LC _n-side of the one end of the third transmission circuit G3 is, to Tsui絡to the gate of the field effect transistor TB _n, The third directly bias power supply terminal 3 from one end of the transmission line LC ₁ side of the transmission circuit G3 is being derived,
Order to have impedance viewed third bias power supply terminal 3 side from one end of the transmission line LC ₁ side of the transmission circuit G3 of the third transmission circuit sufficiently low structure than the characteristic impedance of the G3 of the field effect transistor TB ₁ , TB ₂ ……… T
B _(n-1), a connection point of the transmission line LC ₁ and LC ₂ of the third transmission circuit G3 respectively via the gate parasitic capacitance of TB _n, LC ₂ and L
Connection point connection point ......... LC _(n-1) and LC _n of C _3, the high-frequency component eliminated third予儀from leaking respectively to the transmission line LC _n-side end of the transmission circuit G3 of but with not attenuated, resulting in reflection of the high frequency components in the third end of the transmission line LC ₁ side of the transmission circuit G3 of. For this reason, the conventional cascode type distributed amplifier described above with reference to FIG. 3 has a drawback that it is difficult to provide good broadband amplification characteristics. Therefore, the present invention proposes a novel cascode type distributed amplifier that does not have the above-mentioned disadvantages.

[Means for Solving the Problems]

The cascode-type distributed amplifier according to the present invention is similar to the conventional cascode-type distributed amplifier described above with reference to FIG.
A plurality of (n + 1) transmission lines LA ₁ , LA ₂ ... LA _n , LA _{(n + 1)} sequentially connected in series, and the transmission line LA
_{A first} terminating circuit in which a high-frequency signal input terminal is derived from one end on _one side and a resistor R1 and a capacitor C1 are connected in series with the other end on the transmission line LA _{(n + 1)} side Through a first transmission circuit connected to ground through a plurality of (n + 1) transmission lines LB ₁ , LB ₂ ...
... LB _n and LB _{(n + 1)} , and a high-frequency signal output terminal is led out from one end on the transmission line LB _{(n + 1)} side, and the other end on the transmission line LB ₁ side is connected to a resistance element. A second transmission circuit connected to ground through a second termination circuit in which R2 and the capacitance element C2 are connected in series; and a plurality of n transmission lines LC ₁ , LC connected in series sequentially ₂ ... A third transmission circuit having LC _n and extending a bias power supply terminal from one end of the transmission line LC ₁ , a source connected to ground, and a gate connected to the first transmission circuit connection point between the connection midpoint, LA ₂ and LA ₃ between the transmission lines LA ₁ and LA ₂ of, ......... LA _n and L
A plurality of n field-effect transistors TA ₁ , TA _2, ..., TA _n connected to the connection midpoint between A _{(n + 1)} and the sources are field-effect transistors TA ₁ , TA ₂ ,. … TA _(n-1) , T
Respectively connected to the drain of the A _n, a connection point between the transmission lines LB ₁ and LB ₂ of the second transmission circuit to the drain, a connection point between LB ₂ and _{LB 3 ......... LB (n-1} ) and A connection midpoint between LB _n, a connection midpoint between LB _n and LB _{(n + 1)} , respectively, and a gate connected between transmission lines LC ₁ and LC ₂ of the third transmission circuit, LC ₂
And a connection point between the connection point ......... LC _(n-1) and LC _n between LC _3, a plurality of n that are respectively connected to the transmission line LC _n-side other end of the third transmission circuit Field effect transistors TB ₁ and T
B ₂ ..., TB _(n-1) and TB _n . However, cascode-type distributed amplifier according to the present invention is a cascode type distributed amplifier having such a configuration, the transmission line LC _n-side end of the third transmission circuit,
The transmission line LC _{(n + 1)} and the third termination circuit in which the resistance element R3 and the capacitance element C3 are connected in series are connected to ground in that order, and are connected to the ground. between one end of the transmission line LC ₁ side of the bias power supply terminal and a third transmission circuit that is derived from the circuit, the resistance element R4 having the same resistance value as the resistor element R3 of the third termination circuit is mediated Has been inserted.

[Action / Effect]

According to the cascode type distributed amplifier according to the present invention, the third
One end of the transmission circuit on the transmission line LC _n side is the transmission line LC _{(n + 1)}
And a third terminating circuit in which the resistance element R3 and the capacitance element C3 are connected in series, in that order, connected to ground, and a bias power supply derived from the third transmission circuit. except that between the supply terminal and the transmission line LC ₁ side of the one end of the third transmission circuit, the resistance element R4 having the same resistance value as the resistor element R3 of the third termination circuit is interposed Thus, it has a configuration similar to that of the conventional cascode type distributed amplifier described above with reference to FIG. For this reason, although the detailed description is omitted, a function as a cascode type distributed amplifier similar to the case of the conventional cascode type distributed amplifier described above with reference to FIG. 3 is obtained. However, in the case of the cascode distributed amplifier according to the present invention, as described above, the transmission line LC of the third transmission circuit is used.
One end on the _n side is connected to ground through a transmission line LC _{(n + 1)} and a third termination circuit in which the resistance element R3 and the capacitance element C3 are connected in series, in that order, Furthermore, between one end of the transmission line LC ₁ side of the third bias power supply terminal and a third transmission circuit is derived from the transmission circuit, the same resistance value as the resistor element R3 of the third termination circuit Resistance element R4
Are inserted, the field effect transistors TB ₁ and TB ₂
……… A midpoint of connection between the transmission lines LC ₁ and LC _{2 of} the third transmission circuit, LC ₂ and LC ₃ via the gate parasitic capacitance of TB _n respectively
Intermediate connection point between LC _n and LC _{(n + 1)} A high frequency component which is unavoidable to leak into the connection midpoint between LC _n and LC _{(n + 1)} is transmitted through the transmission line LC _{(n + 1)} to the third point. It can be effectively absorbed and attenuated by the termination circuit. Furthermore, between one end of the transmission line LC ₁ side of the second transmission circuit bias power supply terminal from a third transmission circuit, the resistor element having the same resistance value as the resistor element R3 of the third termination circuit R4 Is inserted, so that the resistance element
Depending on R4, the field-effect transistors TB ₁ , TB ₂ ……… TB _n
Through the gate parasitic capacitance of the respective connection point between the transmission line LC ₁ and LC ₂ of the third transmission circuit, connected between the LC ₂ and LC ₃ midpoint ......... LC _(n-1) and LC _n The high-frequency signal components described above, which are unavoidably leaked to the connection midpoint between them, can be effectively absorbed and attenuated by the resistance element R4,
Therefore, the high-frequency signal component that is liable to leak into the third transmission circuit is transmitted to the transmission line of the third transmission circuit.
It is possible to substantially prevent reflection at one end of the LC ₁ . Therefore, the cascode type distributed amplifier according to the present invention can easily have better broadband amplification characteristics than the conventional cascode type distributed amplifier described above with reference to FIG.

【Example】

Next, an embodiment of a cascode type distributed amplifier according to the present invention will be described with reference to FIG. In FIG. 1, parts corresponding to those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted. The cascode distributed amplifier according to the present invention shown in FIG. 1 has the same configuration as the conventional cascode distributed amplifier described above with reference to FIG. 3, except for the following. That is, one end of the transmission line LC _n-side of the third transmission circuit G3 is, the transmission line LC _{(n + 1)} and the third termination circuit to the resistor element R3 and the capacitor C3 are connected in series B3 And in that order are connected to ground. Between the transmission line LC ₁ side of the one end of the third bias power supply terminal 3 which is derived from the transmission circuit G3 of the third transmission circuit G3, and the resistance element R3 of the third termination circuit B3 A resistance element R4 having the same resistance value is inserted. The above is the configuration of the embodiment of the cascode distributed amplifier according to the present invention. The cascode-type distributed amplifier according to the present invention having such a configuration has the same configuration as the conventional cascode-type distributed amplifier described above with reference to FIG. A function as a cascode-type distributed amplifier similar to that of the conventional cascode-type distributed amplifier described above with reference to FIG. 3 can be obtained. However, in the case of the cascode distributed amplifier according to the present invention shown in FIG. 3, the transmission line LC _{n of} the third transmission circuit G3 is used.
One end on the side is connected to ground through a transmission line LC _{(n + 1)} and a third termination circuit B3 in which a resistance element R3 and a capacitance element C3 are connected in series in that order. because it has a structure which are field effect transistors TB _1, TB ₂ ......... TB _n connection point between the transmission line LC ₁ and LC ₂ of the third transmission circuit G3 respectively via the gate parasitic capacitance of, LC ₂ and the connection point ......... LC _n and LC _{(n + 1)} high frequency components eliminated予儀from leaking each connection point between between LC _3, through the transmission line LC _{(n + 1),} the The third terminating circuit B3 can effectively absorb and attenuate. Between the transmission line LC ₁ side of the one end of the third bias power supply terminal 3 which is derived from the transmission circuit G3 of the third transmission circuit G3, and the resistance element R3 of the third termination circuit B3 Since the resistance element R4 having the same resistance value is interposed, the high-frequency signal component which is supposed to leak as described above can be effectively absorbed and attenuated by the resistance element R4. the third high-frequency signal components lost予儀from leaking to the transmission circuit G3, it is possible to not substantially reflects at one end of the transmission line LC ₁ side. For this reason, according to the cascode type distributed amplifier of the present invention shown in FIG. 1, it is possible to easily have better broadband amplification characteristics than the conventional cascode type distributed amplifier described above with reference to FIG. Can be. Incidentally, in the case of the conventional cascode type distributed amplifier described above in FIG. 3, S ₂₁ parameter, and band amplification characteristics viewed in S ₁₁ and S ₂₂ parameters are obtained as shown FIG. 4, and FIG. 5 respectively At the same time, in the case of the cascode distributed amplifier according to the present invention shown in FIG. 1, the band corresponding to FIG. 3 is the same as that of FIG. 3 under the same conditions as the S ₂₁ parameter and the S ₁₁ and S ₂₂ parameters. Amplification characteristics were favorably obtained as shown in FIGS. 6 and 7, respectively.

[Brief description of the drawings]

FIG. 1 is a connection diagram showing an embodiment of a cascode distributed amplifier according to the present invention. FIG. 2 is a connection diagram showing a conventional basic distributed amplifier. FIG. 3 is a connection diagram showing a conventional cascode type distributed amplifier. FIG. 4 to FIG. 7 are diagrams showing band amplification characteristics for explanation of the present invention. 1 high-frequency signal input terminal 2 high-frequency signal output terminal 3 bias power supply terminals B1, B2, B3 first, second, and third termination circuits G1, G2, G3 first, Second and third transmission paths

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-96007 (JP, A) JP-A-63-120506 (JP, A) JP-A-62-95006 (JP, A) 181017 (JP, U) IEEE MTT-S, Digest pp. 165-168 1989 IEICE Autumn National Convention C-364 (58) Field surveyed (Int. Cl. ⁶ , DB name) H03F 3/60 JOIS PATOLIS

Claims (1)

(57) [Claims] 1. A plurality (n + 1) sequentially connected in series
Number of transmission lines _{LA 1, LA 2 ......... LA n} , have the LA _{(n + 1),} and with which to derive the high frequency signal input terminal from one end of the transmission line LA ₁ side, the transmission line LA The other end on the _{(n + 1)} side is a _{first terminal in} which a resistance element R1 and a capacitance element C1 are connected in series.
A first transmission circuit connected to ground through a terminating circuit, and a plurality of (n + 1) transmission lines sequentially connected in series
LB ₁ , LB ₂ ... LB _n , LB _{(n + 1)} , and the transmission line
LB _{(n + 1)} at one end with which to derive the high frequency signal output terminal from the side, the second end of the other end of the transmission line LB ₁ side and the resistance element R2 and the capacitor C2 are connected in series A second transmission circuit connected to ground through a circuit for use, and a plurality of n transmission lines LC ₁ , LC ₂ connected in series
... A third transmission circuit having LC _n and extending a bias power supply terminal from one end of the transmission line LC ₁ , a source connected to ground, and a gate connected to the first transmission line A connection point between the transmission lines LA ₁ and LA _{2 of the} circuit, a connection point between LA ₂ and LA ₃ ..., A plurality of points respectively connected to connection points between LA _n and LA _{(n + 1)} n field effect transistors TA
₁ , TA ₂ ... TA _n and the source are the field effect transistors TA ₁ , TA ₂ ... TA
_(n-1) , respectively connected to the drains of TA _n , the drains being connected midpoints between the transmission lines LB ₁ and LB _{2 of} the second transmission circuit,
A connection midpoint between LB ₂ and LB ₃ ... a connection midpoint between LB _(n-1) and LB _n, a connection midpoint between LB _n and LB _{(n + 1)} , respectively;
Connection point between the transmission line LC ₁ and LC ₂ of the gate the third transmission circuit, a connection point between the LC ₂ and _{LC 3, ......... LC (n-} 1) and a connection point between the LC _n , The transmission line LC _n of the third transmission circuit.
A cascode-type distributed amplifier having a plurality of n field-effect transistors TB ₁ , TB _2, ..., TB _(n-1) , TB _n connected to the other end of the third transmission line, respectively. One end of the circuit on the side of the transmission line LC _n passes through the transmission line LC _{(n + 1)} and a third termination circuit in which a resistance element R3 and a capacitance element C3 are connected in series in that order. , is connected to ground, the bias power supply terminal which is derived from the third transmission circuit, between one end of the third the transmission line LC ₁ side of the transmission circuit, the third termination circuit A cascode-type distributed amplifier, wherein a resistance element R4 having a resistance value equal to that of the resistance element R3 is interposed.