XVIII-th International Conference on
Electromagnetic Disturbances
Vilnius, Lithuania, 25-26 September 2008
EMD 2008
STRUCTURES AND CHARACTERISTICS OF NEW MULTIPLE BROADBAND AMPLIFIERS FOR RA-
DIOCOMMUNICATION SYSTEMS
Giennadij CZAWKA
e-mail: ggc@pb.edu.pl
Bialystok Technical University, Poland
Summary: New structures of original multiple broad- These structures provide destruction of undesirable sig-
band amplifiers for radiocommunication systems are nals without of some filter mechanical commutations.
proposed in the work. These amplifiers consist of sev-
eral amplify blocks and special multiple phase and fre- 2. Structures of the multiports for phase
quency commutators. Base properties and characteristics and frequency channel multiplexing
of multiple amplifiers are presented. These devices may
Main blocks of multiport broadband amplifiers are mul-
be used for reduction of electromagnetic disturbances in
tiport frequency and phase commutators. Whole struc-
different radio systems.
tures of the multiports for phase and frequency channel
multiplexing are shown in Fig.1.
Keywords: electromagnetic disturbances, multiport am- Determinations of the main blocks are:
plifiers, phase and frequency commutators, CAD. Phase commutator - double side multiport that pro-
vides a given phase distribution of output signals with
1. Introduction excitation of separate inputs of the network (Fig.1,a).
The paper presents EMD modeling, structures and fre- Inversely, phase commutator provides sum signal of all
quency characteristics of multiport broadband amplifiers excitation generators in some one output only for differ-
with phase and frequency channel for different radio ent phase distribution of the generators. These commuta-
system [1-2]. Main topic of the paper is a computer tors may be synthesized with use of special two-channel
analysis of power parameters and phase characteristics phase blocks - hybrids [1,3,4].
of these amplifiers at given frequency band. Frequency commutator - double side multiport is pro-
Different structures of multiport amplifiers are consid- viding given distributions of frequency bands on out-
ered and analyzed in paper. At first, structures of the puts with different excitation of inputs of the network
multiports for phase and frequency channel multiplexing (Fig.1, b). Synthesis of the frequency commutators is
in radio systems and structures and parameters of hybrid made by use of special two- or multi- channel blocks:
and phase commutators are presented. Then two-channel diplexers and multiplexers [2, 5-9].
amplifier with hybrids and without and with diplexers, Represented frequency and phase broadband commuta-
four-channel amplifier with hybrids and multiplexers tors provide necessary frequency and phase signal dis-
and eight-channel amplifier with hybrids, diplexers and tributions on all amplify block in whole multiport ampli-
multiplexers are described and simulated [3-9]. fier in given frequency band.
a) R1 1 1 b) R1 1 1
E1 Phase R1 R1 Kpi
commu-
φ 1 E1 Frequency ∆ f1 1 2 n
1
Rn n tator n Rn n
commu-
tator n
0,5
SN Rn SN Rn
En φ n En 0
∆ f1 ∆ f2 ∆ fn
∆ fn f
f1 f2 f n-1
Fig.1. Phase (a) and frequency (b) multiport commutators
79
2. Structure and parameters of hybrid The matrix (1) (Fig.4,b) shows that this balun struc-
and phase commutators ture is the theoretical uncoupled-matched network on
the whole frequency axis. But this structure ensures an
As written above a main block for design of broadband
equal ratio power dividing and the equal/opposite
phase commutators is balun (hybrid) [1,3,4]. Structures
phases of the output signals with different excitations of
of scattering matrix and its non-diagonal blocks of ideal
the inputs (Fig.2) for small electrical length or about
hybrid is:
θ = kπ only. For electrical length θ = 0.5(2k+1)π this
0 Tt 1 1 1 hybrid has whole signal on one output only (Fig.3,c).
SN = , T2 = (1)
2 1 − 1
This property allows using balun as a frequency commu-
T 0
tator - a different distribution of the output signals for
Then, this network realizes equal and opposite phases different frequency bands [2].
of the output signals with excitations of some inputs as The hybrid is base element for design of four-channel
shown in Fig.2. phase commutator (Fig.3). This commutator consist of
1 3 o 1 3 o four hybrids and provides four combinations of phase
0 0
H H distributions (0 0 and 180 0 ) or: (+1) and (-1) – of output
2 4 o 2 o
0 4 180 signals with excitations of different one input. This
commutator is one of base multiport for design of four-
Fig.2. Principle of the hybrid operation channel multiport amplifier [1,3,4].
An example of the balun realization as microstrip or
a) 1 H H
1
b) 1 1 1 1
coaxial lines, ideal scattering matrix and corresponding 1 1 1 − 1 − 1
T4 =
3 3
frequency characteristics are represented in Fig.4.
2 1 − 1 1 − 1
2 2
The elements of the hybrid scattering matrix may be H H
calculated for chosen electrical line length θ [1,5]:
4 4 1 − 1 − 1 1
β = 1 /( 2 + i tg θ) , γ = β secθ (2) Fig.3. Structure (a) and transmission matrix
of 4-port phase commutator
a) b) c)
γ β
2R 1 ρ =R 2 3 R 1
,
γ
0 0 γ β 0,8
E1 4 β −γ
=
0 0 0,6
2R SN
2 γ β 0 0 0,4
β
β − γ
R 0 0
ρ =R 2 E2 0,2
θ
o
0 90 180 270 360
Fig.4. Structure (a), ideal scattering matrix (b) and characteristics (c) of the microstrip hybrid (balun)
3. Two-channel amplifier with hybrids 4. Two-channel amplifier with hybrids and diplexers
Structure and frequency characteristics of two-channel Structure and frequency characteristics two-channel am-
amplifier with two hybrids for in-phase and unti-phase plifier with two hybrids and two diplexers are shown in
excitations are shown in Fig.5. Fig.6. This is the same structure as it shown in Fig.5
Two-channel amplifier consist of two amplify blocks with adding input and output diplexers only.
and two hybrids. Input hybrid is power divider but out- Input diplexer divides the whole frequency band in two
put hybrid is summing power network. With change of parts, but output diplexer connects its in common output
excitation input a double power signal (in comparison of of amplifier. Such, for low frequency band in-phase ex-
power of single amplify block) appear in corresponding citation we have for every amplify blocks, but for high
output of multiport amplifier. frequency band – anti-phase excitation.
With excitation of the first input of multiport amplifier Frequency power characteristics in output of input hy-
in-phase signals excite every amplify block, and we brid is presented in Fig.6,a; the same power characteris-
have output signal on the first output only (Fig.5,a,b). tics for output hybrid – in Fig.6,b. Third-order ring di-
Inversely, with excitation of the second input of ampli- plexer [2,4] was used for computer simulations of whole
fier anti-phase signals excite amplify blocks, and output multiport amplifier. We see that diplexers provide divid-
signal appear in the second output only (Fig.5,c,d). Dif- ing of all frequency bands in two parts.
ference between phase characteristics is shown in For common frequency of these band parts a phase dif-
Fig.5,b,d. ference (90 0) of obtained signals exist in outputs of first
Both inputs and both outputs of whole amplifier are un- diplexer (Fig.6,c). Then phase shifters must be used in
coupling because of using of hybrid (1). Computer outputs of first diplexer and the same shifter in inputs of
simulation of all frequency characteristics was made second diplexer. Using of these phase shifters allow to
with use hybrid realization as it shown in Fig.3. receive good parameters of whole amplifier.
80
a) Pnorm b) Arg(U)
1.00 1
0
A -30 1, 2
H H
0.75 A
2 -60
1
0.50 -90
2
-120
0.25
-150
0.00 -180
0 20 40 60 80 100 f , MHz 0 20 40 60 80 100 f , MHz
c) Pnorm d) Arg(U)
1.00 200
1
A 2
H H
0.75 100
2
A
2
0.50 1
0.00
1
0.25 -100
0.00 -200
0 20 40 60 80 100 f , MHz 0 20 40 60 80 100 f , MHz
Fig.5. Structure and power (a,c) and phase (b,d) characteristics two-channel amplifier with two hybrids
for in-phase and unti-phase excitations
a) Pnorm
1.00
3 0.75
1
A 2
D H H D 0.50
2 A 1
4
0.25
0.00 .
0 20 40 60 80 100 f , MHz
b) Pnorm c) Arg(U)
1.0 200
3 4
0.8
100
2
0.6
0.00 2
0.4 1
0.2 -100
0.0 -200
0 20 40 60 80 100 f , MHz 0 20 40 60 80 100 f , MHz
Fig.6. Structure and power (a,b) and phase (c) characteristics of two-channel amplifier
with two hybrids and two diplexers
81
2
A
H H H H
1 A 3
6
M M
A
4
H H H H
A 5
a) Pnorm b) P6 = P Σ
1.0 1.0
2 3 5 6
4
0.8
0.6
0.5
0.4
0.2
0.0 0.0
0 20 40 60 80 100 f , MHz 0 20 40 60 80 100 f , MHz
Fig.7. Structure and channel power (a) and output power (b) characteristics of four-channel amplifier
with eight hybrids and two multiplexers
5. Four-channel amplifier with hybrids 6. Eight-channel amplifier with hybrids,
and multiplexers diplexers and multiplexers
This multiport amplifier consist of four amplify blocks, Last multiport amplifier consist of eight amplify blocks,
two four-channel phase commutators (as shown in Fig.3) input and output phase commutators (every one consists
and two four-channel frequency commutators – multi- of seven hybrid), two diplexers and two multiplexers for
plexers (Fig.7). Input multiplexer divides whole fre- four frequency bands (Fig.10).
quency band in four parts, but output multiplexer pro- Whole multiport complicated structure has three inputs
vides connecting of output phase commutator to com- and three outputs providing three main regimes of mul-
mon output of whole amplifier. tiport amplifier (Fig.9).
Input and output phase commutators provide different With excitation of the first input all amplify blocks have
phase excitation in input of all amplify blocks (matrix in in-phase excitation (according to the hybrid operation,
Fig.3,b) and then we have different combinations of fre- Fig.2); then sum of power blocks (8P 0 in Fig.9) evolves
quency bands in output of amplifier blocks (P0 in Fig.8). in first output only (thick arrows in Fig.10). Resistance
Sum output power of whole amplifier is four times lar- in this figure included for balance of uncoupled input.
der from power of single amplifier block (4P0 in Fig.8). With excitation of the second input whole frequency
Normalized computer simulated frequency power char- band divides in two parts (as for amplifier, Fig.6). Then
acteristics in inputs of output multiplexer and output of one half of amplify blocks has in-phase excitation (+1),
whole amplifier are shown in Fig.7,a,b. second half - anti-phase (-1).
P P out P
P1
4P0
8P 0
P2 P3
P0 4P 0
2P 0
f f f f
1 2 3
Fig.8. Frequency power characteristics of amplify f
blocks for different combinations of excitations (P0) Fig.9. Frequency output power characteristics for
and whole amplifier (4P0) excitation of different inputs of whole amplifier
82
Power (4P 0 in Fig.9) evolves in two frequency bands Power (2P 0 in Fig.9) evolves in four frequency bands
in the second output of whole amplifier only in this case in the third output of whole amplifier in this case
(double arrows in structure, Fig.10). (quadruple arrows in structure, Fig.10).
With excitation of the third input whole frequency band Corresponding frequency channel and output power
divides in four parts (as for amplifier, Fig.7). Then characteristics in different points of the amplifier for dif-
every pair of all amplify blocks has in-phase excitation ferent excitation inputs of whole multiport broadband
different according to matrix (Fig.3,b). amplifier are shown in Fig.10.
A
H H
Inp 3 M A M Out 3
A
H H H H
A
Inp 2 D D Out 2
A
H H
A
R R
A
H H H H H H
Inp 1 A Out 1
a) Pnorm Outputs of whole amplifier b) Pnorm Outputs of whole amplifier
1.00 1.00
0.75 0.75 Outputs of diplexer
Outputs of first hybrid
0.50 0.50 Output of amplify blocks
0.25 Output of amplify blocks 0.25
0.00 0.00
0 20 40 60 80 100 f , MHz 0 20 40 60 80 100 f , MHz
Outputs of input multiplexer d) Pnorm Outputs of whole amplifier
c) Pnorm
1.0 1.0
0.8 0.8
0. 0.6 Outputs of amplify blocks
0. 0.4
4
0.2 0.2
0.0 0.0
0 20 40 60 80 100 f , MHz 0 20 40 60 80 100 f , MHz
Fig.10. Structure and normalized channel and output power characteristics of eight-channel amplifier
with fourteen hybrids, two diplexers and two multiplexers in different points for different excitation inputs of amplifier:
a) excitation of input 1, signal in output 1, b) excitation of input 2, signal in output 2,
c, d) excitation of input 3, signal in output 3
83
Acknowledgments ference on Circuit Theory and Design, ECCTD'01, Espoo,
Finland, August 28 – 31, 2001: III-117-120.
This work was supported by the Polish Government
Committee of Scientific Research in Technical Univer- 4. Czawka, G. 2002. Synthesis of broadband microstrip un-
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on Microwaves, Radar and Wireless Communications
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5. Czawka G. 1998. A new ring microstrip diplexer, XII In-
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