US-12620949-B2 - Amplifier circuit arrangement and electronic device

Abstract

An amplifier circuit arrangement for amplifying at least one input signal to an output signal for delivery to a load. The amplifier circuit arrangement includes at least one four-port hybrid coupler, a main amplifier having an input terminal for receiving a first input signal and coupled to a first port of the hybrid coupler, an auxiliary amplifier having an input terminal for receiving a second input signal and coupled to the second port of the hybrid coupler, a negative resistance amplifier circuit coupled to the third port of the hybrid coupler. The negative resistance amplifier circuit receives a signal from the hybrid coupler via the third port and returns an amplified signal back to the third port of the hybrid coupler. At least one of the auxiliary amplifier and negative resistance amplifier circuit selectively operates in combination with the main amplifier circuit.

Inventors

• Paul Gareth Lloyd

Assignees

• ROHDE & SCHWARZ GMBH & CO. KG

Dates

Publication Date

20260505

Application Date

20230420

Claims (20)

1. 1 . An amplifier circuit arrangement for amplifying at least one input signal to an output signal for delivery to a load, the amplifier circuit arrangement comprising: at least one four-port hybrid coupler, a main amplifier having an input terminal for receiving a first input signal and being coupled to a first port of the hybrid coupler, an auxiliary amplifier having an input terminal for receiving a second input signal and being coupled to the second port of the hybrid coupler, a negative resistance amplifier circuit being coupled to the third port of the hybrid coupler and having a reflection coefficient greater than or equal to 1, wherein the negative resistance amplifier circuit is configured to receive a signal from the hybrid coupler via the third port and to return an amplified signal thereof back to the third port of the hybrid coupler, wherein at least one of the auxiliary amplifier and the negative resistance amplifier circuit being selectively operable to operate in combination with the main amplifier circuit.
2. 2 . The amplifier circuit arrangement of claim 1 , further comprising an output terminal connected to the fourth port for providing the output signal and for coupling the amplifier circuit arrangement to the load.
3. 3 . The amplifier circuit arrangement of claim 1 , wherein the third port is an isolated port of the hybrid coupler.
4. 4 . The amplifier circuit arrangement of claim 1 , wherein the negative resistance amplifier circuit comprises a first and a second terminal, wherein the first terminal acts as well as input and output terminal of the negative resistance amplifier circuit and wherein the second terminal is coupled to a reference voltage.
5. 5 . The amplifier circuit arrangement of claim 1 , wherein the negative resistance amplifier circuit comprises a RF reflection amplifier.
6. 6 . The amplifier circuit arrangement of claim 1 , wherein the negative resistance amplifier circuit comprises at least one IMPATT diode.
7. 7 . The amplifier circuit arrangement of claim 1 , wherein the negative resistance amplifier circuit comprises at least one circulator circuit that is connected to an output of a reflection amplifier or another circulator circuit.
8. 8 . The amplifier circuit arrangement of claim 7 , comprising a plurality of circulators and reflection amplifier that are connected in a Daisy chain configuration.
9. 9 . The amplifier circuit arrangement of claim 1 , further comprising a power splitter configured to split a received input signal into the first input signal and the second input signal and to feed the splitted first and second input signals to the respective input terminals of the main amplifier and auxiliary amplifier, respectively.
10. 10 . The amplifier circuit arrangement of claim 9 , wherein the power splitter is an uneven 3-way Wilkinson splitter.
11. 11 . The amplifier circuit arrangement of claim 1 , wherein the hybrid coupler comprises at least one of: a Branch-line coupler, a lumped elements coupler, a coupled-line coupler, a Lange coupler.
12. 12 . The amplifier circuit arrangement of claim 1 , wherein the hybrid coupler is a quadrature coupler.
13. 13 . The amplifier circuit arrangement of claim 1 , wherein the hybrid coupler is a ring hybrid coupler.
14. 14 . The amplifier circuit arrangement of claim 1 , further comprising at least one matching network, wherein each matching network is coupled to a respective one of the four ports of the hybrid coupler in order to perform impedance transformation, wherein at least one of the matching networks comprises a transmission line or a lumped element.
15. 15 . The amplifier circuit arrangement of claim 1 , wherein a characteristic impedance of the hybrid coupler is configured to match a loading impedance of the load.
16. 16 . The amplifier circuit arrangement of claim 1 , further comprising a sharpening filter coupled between the negative resistance amplifier and the third port.
17. 17 . The amplifier circuit arrangement of claim 1 , wherein the negative resistance amplifier comprises a control terminal for receiving a control signal and wherein the negative resistance amplifier is configured such to set a predetermined magnitude of the reflection coefficient depending on the received control signal.
18. 18 . The amplifier circuit arrangement of claim 1 , wherein the gain of the negative resistance amplifier is below 3 dB and in particular in the range of 1 dB or below.
19. 19 . An electronic device comprising an amplifier circuit arrangement for amplifying at least one input signal to an output signal for delivery to a load, the amplifier circuit arrangement comprising: at least one four-port hybrid coupler, a main amplifier having an input terminal for receiving a first input signal and being coupled to a first port of the hybrid coupler, an auxiliary amplifier having an input terminal for receiving a second input signal and being coupled to the second port of the hybrid coupler, a negative resistance amplifier circuit being coupled to the third port of the hybrid coupler, wherein the negative resistance amplifier circuit is configured to receive a signal from the hybrid coupler via the third port and to return an amplified signal thereof back to the third port of the hybrid coupler; wherein at least one of the auxiliary amplifier and the negative resistance amplifier circuit being selectively operable to operate in combination with the main amplifier circuit.
20. 20 . The electronic device of claim 19 , wherein the electronic device comprises at least on one of: a radio transmitter, a TV transmitter, a radio base station, a bargaining chip, a broadband amplifier.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims the benefit of U.S. provisional application No. 63/341,016, filed on May 12, 2022, the content of which is hereby incorporated by reference in its entirety. TECHNICAL FIELD The present invention relates to an amplifier circuit arrangement for amplifying at least one input signal to an output signal for delivery to a load. The present invention further relates to an electronic device. BACKGROUND OF THE INVENTION Although applicable in principle to any amplifier, the present invention and its underlying problem will be hereinafter described in conjunction with amplification of radio frequency (RF) signals, in particular for use in a wireless communication systems. In particular in a wireless communication system, a transmitter employs power amplifiers to boost signal power for radio transmission. To be efficient in occupying frequency spectrum, modern communication signals have a large peak-to-average power ratio (PAR). The capability to reach peak power and to maintain energy efficiency at the average power levels is contradictory for conventional single branch power amplifiers. More sophisticated power amplifier architectures employ multiple power amplifier branches to satisfy both the power and the efficiency requirements. Among these power amplifier architectures, the most widely used in wireless infrastructures is the so-called Doherty power amplifier. A Doherty power amplifier consists of at least two power amplifier branches, namely a main branch and an auxiliary branch. In operation, an auxiliary power amplifier in the auxiliary branch injects power into a main power amplifier in the main branch in order to modulate its effective load impedance according to a specific pattern such that total efficiency is maximized not only at the peak-power but also at the average-power level. A so-called 3-way Doherty power amplifier comprises three power amplifier branches, namely a main power amplifier and two auxiliary power amplifiers. The first auxiliary power amplifier modulates the load of the main power amplifier the same as that in a 2-way Doherty power amplifier, to maximize efficiency at the low and medium power levels. The second auxiliary power amplifier modulates the loads of both the main and first auxiliary power amplifiers to maximize efficiency at the peak power level. As a result, total efficiency at three different power levels can be maximized. The energy saving is considerable in high PAR applications. U.S. Pat. No. 10,749,478 B2 describes an amplifier arrangement similar to the 3-way Doherty power amplifier described above. This amplifier circuit arrangement comprises a main branch and two auxiliary power amplifiers that are selectively operated. Suitable input signals are provided to each one of the main and auxiliary power amplifiers. The generation of these input signals, however, is not trivial and needs complex calculation and synthesizing effort. This applies particularly to the input signals provided to the auxiliary power amplifier that is coupled to the isolated port of the hybrid coupler. The solution described in U.S. Pat. No. 10,749,478 B2 uses an active signal injection into the isolated port of the hybrid coupler. The required signal conditioning and shaping of this signal is complex since the distortion characteristic incident to the isolated port must match the signal emerging from it. Basically, the generation of the injected signal correspond to some kind of “predictive post-correction” which needs a very complex calculation. The calculation and synthesis of the input signals needs significant calculation effort which goes to the expense of the performance. The challenge of maintaining high performances in particular for high efficiency amplification, however, makes the whole power amplifier circuit arrangement expensive. Against this background, there is the need to provide a more efficient, simplified power amplifier circuit arrangement with improved performance and at the same time reduced complexity and cost. SUMMARY OF THE INVENTION The present invention provides an amplifier circuit arrangement and an electronic device having the features of the independent claims. According to a first aspect, an amplifier circuit arrangement for amplifying at least one input signal to an output signal for delivery to a load is provided, the amplifier circuit arrangement comprising: at least one four-port hybrid coupler, a main amplifier having an input terminal for receiving a first input signal and being coupled to a first port of the hybrid coupler, an auxiliary amplifier having an input terminal for receiving a second input signal and being coupled to the second port of the hybrid coupler, a negative resistance amplifier circuit being coupled to the third port of the hybrid coupler, wherein the negative resistance amplifier circuit is configured to receive a signal from the hybrid coupler via the third port and to return