KR100595736B1 - Design method of low noise amplier in portable internet time division duplexing antenna part and the low noise amplier - Google Patents

Abstract

The present invention relates to a low noise amplifier design method and a low noise amplifier of the portable Internet time division duplex antenna stage, the limiter diode (Limiter Diode) added in the low noise amplifier 110 without the implementation of the limiter 140 circuit added to the outside The receiver low noise amplifier 110 can withstand the leakage signal and the reflected wave power of the transmission power alone, and the intermodulation and tertiary distortion components generated by the limiter diode are not radiated to the antenna 100, and the low noise amplifier 110 is designed. This ensures sufficient signal purity for the final output power, resulting in improved waveform quality and spectral mask characteristics, and the need for external limiter 140 circuitry. This eliminates the need for concise system design and cost savings.

Portable Internet, TDD, Antenna, Low Noise Amplifier, LNA

Description

DESIGN METHOD OF LOW NOISE AMPLIER IN PORTABLE INTERNET TIME DIVISION DUPLEXING ANTENNA PART AND THE LOW NOISE AMPLIER}             

1 is a block diagram of a portable Internet time division duplex antenna stage using a circulator according to the prior art.

Figure 2a is a block diagram for explaining the generation of intermodulation and third-order distortion of the transmission power due to the leakage signal of the circulator and the reflected wave of the limiter according to the prior art.

2b is a view showing the change in output in the frequency domain according to FIG.

3A is a block diagram illustrating a balanced low noise amplifier protected from a transmitter leakage signal in accordance with the present invention.

3b is a view showing an output change in the frequency domain according to FIG.

4 is a flowchart of a method for designing a balanced low noise amplifier of a portable Internet time division duplex antenna stage according to the present invention;

Explanation of symbols on the main parts of the drawings

100: antenna

110: low noise amplifier (LNA)

120: power amplifier (PA)

130: circulator

130a: transmitter circulator

140: limiter

200: Balanced Path Low Noise Amplifier

210, 210 ': 90 ° 3dB Hybrid

220, 220 ': limiter diode

230: first three stage amplifier

230 ': second 3-stage amplifier

The present invention relates to a low noise amplifier design method and a low noise amplifier of the portable Internet time division duplex antenna stage, more specifically, a limiter added in the low noise amplifier 110 without the implementation of a limiter 140 circuit added to the outside With only a diode, the receiver low noise amplifier 110 can withstand the leakage signal and the reflected wave power of the transmission power, and the intermodulation and tertiary distortion components generated by the limiter diode are not radiated to the antenna 100. Such a low noise amplifier The design method ensures sufficient signal purity for the final transmission power, thereby improving waveform quality and spectrum mask characteristics and simultaneously implementing additional limiter 140 circuits externally. Portable Internet Time Segmentation Enables Concise System Design and Cost Reduction As No Necessity Protective LNA of the antenna terminal and to a method for the low-noise amplifier.

Recently, wireless communication network has evolved from 3rd generation (3G) asynchronous wideband code division multiple access (CDMA) system that processes voice and video together in synchronous code division multiple access (CDMA) system mainly for voice calls. Furthermore, the Portable Internet technology, which enables users to access the Internet anytime and anywhere to obtain the necessary information by allowing them to use the Internet wirelessly while maintaining high speed mobility and high speed data transmission, has emerged as a major concern. Doing. The mobile Internet is now called Wi Bro, and service providers and equipment manufacturers form research groups to set international standards.

The wireless communication network constituting the portable Internet service system commonly adopts a code division multiple access (CDMA) method, and uses a frequency division duplex (FDD) according to a division duplex (DD) method. Division Duplex (TD) and Time Division Duplex (TDD) are largely divided. Recently, with Orthogonal Frequency Division Multiplexing (OFDM) transmission scheme for processing high speed data while maintaining high mobility, time division duplexing (TDD) considering the frequency efficiency of the user The method is commercially available. The frequency division duplex method is a full duplexer that transmits and receives frequency bands differently so that transmission and reception do not affect each other simultaneously. The frequency band is used but the transmission time is different so that it does not interfere with transmission and reception.

In devices that use high output power such as base stations, access points (APs), and repeaters in portable Internet service systems that use the time-division duplex method, a single antenna serves to transmit / receive with a single antenna. The use of circulators has been considered.

1 is a block diagram of a portable Internet time division duplex antenna stage using a circulator according to the prior art.

The prior art in which the transmission and reception antennas are shared by each device (base station, access point, repeater, etc.) of the portable Internet service system using the time division duplex method includes a circulator 130 as shown in FIG. By using the directionality of the 130, the transmission and reception signals do not influence each other. The circulator, which is a three-terminal signal branch circuit element, has three terminals surrounded by a 120 degree angle, and a magnetic body such as a resonance plate and a ferrite is disposed therein. Power is incident on one of the three terminals configured in the circulator, and only one of the other two terminals is output, but not the other. Thus, a three-terminal device transmits energy only to a terminal in a specific direction as if rotating in a directional manner.

The power amplifier 120 is turned on during the transmission cycle using the directionality of the circulator 130 to transmit the transmission power toward the antenna 100, and the received signal from the antenna 100 during the reception cycle is low noise. It is to be received in the direction of the amplifier (110). However, the actual circulator has a leakage signal for the reverse direction in addition to the directionality, so that the power amplifier 120 is turned on during the transmission cycle to transmit the transmission power to the antenna 100 through the circulator 130. When transmitting, at the same time, about -20 dB of transmission power is applied to the receiver in the reverse direction. A base station, an access point, a repeater, and the like of a portable Internet service system require 43dBm, that is, 20W or more transmission power. Due to the leakage signal, a leakage power of about 23dBm (200mW) is applied to the receiving end.

In addition, when a problem occurs in the antenna 100 and an antenna feeder cable during operation, and the 50 Ω characteristic impedance of the antenna stage is mis-matched, the power of several tens of W to be transmitted to the antenna 100 is circular. It is applied to the receiver through the radar 130.

As described above, in the prior art as shown in FIG. 1, installation cost and the like can be reduced by reducing the antenna and the antenna coaxial cable than using two antennas, but in operation, the receiver low noise amplifier 110 may operate at several hundred mW to several tens of mW. When the power of W is applied, the low noise amplifier 110 may be saturated or the internal circuit may be destroyed due to the application of high power.

FIG. 2A is a block diagram illustrating intermodulation and third-order distortion generation of transmission power due to leakage signals of a circulator and reflected waves of a limiter according to the prior art, and FIG. 2B is a diagram illustrating output variation in a frequency domain according to FIG. The figure shown.

In the case of the configuration as shown in FIG. 1, as described above, the power of several hundred mW to several tens of W is applied to the receiver low noise amplifier 110 so that the internal circuit is destroyed due to the low noise amplifier 110 being saturated or high power being applied. To prevent this, by configuring the limiter 140 circuit in front of the low noise amplifier 110 as shown in Figure 2a to suppress the limiter 140 circuit even if high power is applied to protect the low noise amplifier 110. . In addition, the low noise amplifier 110 is turned off during the transmission cycle in order to prevent a small power transmitter noise, which is not suppressed by the limiter 140, from leaking and being amplified at the receiver through the low noise amplifier 110. It is designed to maximize the isolation of transmission and reception signals by turning it off. Isolation of the signal (isolation) is the degree to which each signal separates when multiple signals are used in the same circuit at the same time, a measure of how much less interference between each signal. In the case of the reception period, the low noise amplifier 110 is turned on to amplify the received signal from the antenna 100. In this case, the transmitter power amplifier 120 is designed to be in an off state.

However, according to this conventional technology, even if the leakage signal of the transmission power leaked during the transmission cycle is suppressed by the limiter 140, the low noise amplifier 110 is in an off state and is not a 50 kHz characteristic impedance, thereby suppressing the leakage signal. There is a problem that causes the reflection back to the antenna stage. In addition, the limiter 140 circuit is composed of a diode which is a non-linear element, and inter-modulation (IM) such as a third-order distortion component is generated in addition to the reflected leakage signal. The limiter reflected wave having the third-order distortion component travels back to the antenna terminal along the reverse direction of the receiving end circulator 130b, and is reflected from the transmitting signal and the limiter 140 amplified by the power amplifier 120 of the transmitting end. In addition to the on-leakage signal, the third order distortion component generated while passing through the limiter 140 is combined.

2A and 2B, a step of outputting a large output transmission power at a transmitting end (S100), a reverse leakage signal of transmission power is applied to a receiving end to generate a loss of 20 dB (S110), and a reverse leakage signal. In step S120, the limiter reflected wave combined with the intermodulation and tertiary distortion components thereof is reflected by the limiter 140, and the limiter reflected wave passes through the receiving end circulator 130b (S130). It can be seen that the step (S140), etc., in which the final transmission power having the intermodulation and tertiary distortion components are output to the antenna stage is performed.

As a result, even if only the transmission signal is output from the transmitter power amplifier 120, the final transmission power is radiated through the antenna 100 with the intermodulation and third distortion components at the antenna stage according to the influence of the peripheral circuit configuration, Due to the generation of intermodulation and third-order distortion components that affect the signal purity, which is very important, the performance of the mobile Internet service system is degraded due to the deterioration of the bit error rate (BER) and the waveform quality. And data corruption can occur.

Accordingly, an object of the present invention is to solve the conventional problems as described above, by applying the characteristics of the balanced amplifier to the low-noise amplifier rather than configuring the additional limiter circuit 140 to the outside without limiter diode ( By adding only limiter diode, it can endure leakage signal and reflected wave power of transmission power, and prevents the intermodulation and tertiary distortion components generated from the limiter diode from radiating to the antenna 100, and the low noise amplifier design method Ensuring sufficient signal purity for the output transmit power improves waveform quality and spectrum mask characteristics, and eliminates the need to implement additional limiter 140 circuitry externally. It enables simple system design and cost reduction.

The low-noise amplifier of the portable Internet time division duplex antenna stage according to the present invention for achieving the above object is a transmitting stage power amplifier for radiating transmission power to the outside through the transmitting and receiving antenna (100), the antenna (100) 120, a low noise amplifier of a receiver to which a received signal is applied from the outside through the antenna 100, and the power amplifier 120 is turned on and the low noise amplifier is turned off in a transmission period to transmit power. In the reception cycle, the low noise amplifier is turned on and the power amplifier 120 is turned off to include a circulator 130 for receiving a reception signal to share transmission and reception with one antenna. In constructing a low noise amplifier of an antenna stage for providing a portable Internet service in a time division duplex method, the low noise amplifier suppresses a leakage signal of transmission power to prevent leakage. It is formed in the equilibrium structure with limiter diodes 220 and 220 'therein to prevent the force from being applied to the rear stage, so that the entire input stage is matched to the 50 Ω characteristic impedance and saturated due to the reverse leakage signal applied to the receiving stage when the transmission power is output. It is characterized in that the balanced low noise amplifier 200 to prevent the internal circuit is destroyed.

Preferably, the balanced low noise amplifier 200 has a ground terminal connected to a 50 Ω resistor so that the reflected wave does not return to the input, but is applied to the 50 kHz termination by the sum and difference of the two signal phases so that the input and the terminal are consumed. A first three stage amplifier 230 and a second three stage amplifier 230 coupled between the 90 ° 3 dB hybrid 210 and 210 ′ of the output stage and the 90 ° 3 dB hybrid 210 and 210 ′ of the input and output stages, respectively. ') Is further provided, wherein the 90 ° 3dB hybrid 210 of the input stage receives the leakage signal of the transmission power applied to the balanced low noise amplifier 200 through the input terminal and the first three stage amplifier 230. And split the signal divided by the second three stage amplifier 230 'into two branches so that the signal has a 90 ° phase difference, and the 90 ° 3 dB hybrid 210' of the output stage is the first three stage amplifier 230 and In-phase synthesis of the two signals passed through the second three stage amplifier 230 ′, The meter diodes 220 and 220 'have one end connected to an input terminal of a first stage amplifier of the first three stage amplifier 230 and the second three stage amplifier 230', and the other end is grounded. do.

Preferably, the first three-stage amplifier 230 and the second three-stage amplifier 230 'is characterized by consisting of a low noise transistor.

The method for designing a low noise amplifier of a portable Internet time division duplex antenna stage according to the present invention is applied to a base station, an access point and a repeater for providing a portable Internet service, and has a low noise of an antenna stage for sharing transmission and reception with one antenna. In the method of designing an amplifier, in a transmission period, a step (S200) in which a large output transmission power is output from a transmitting end, and a leakage signal of the transmission power is applied to the receiving end so that the transmission power output from the transmitting end is lost by 20 dB ( S210 and a limiter reflected wave in which intermodulation and tertiary distortion components are combined as the leakage signal applied to the receiver passes through the limiter diodes 220 and 220 'inside the balanced low noise amplifier 200 (S220). The reflected wave power is 50 kHz termination through the 90 ° 3dB hybrid (210, 210 ') ground terminal of the input and output terminals configured inside the balanced low noise amplifier 200. When the input impedance to the balanced low noise amplifier 200 is consumed and matched to the 50 kHz characteristic impedance (S230), and as the reflected wave power is consumed, the final power of the balanced low noise amplifier 200 is not combined with the intermodulation and tertiary distortion components. The transmission power is characterized by consisting of the step (S240) and the like radiated through the antenna 100.

In the following description of the preferred embodiments of the present invention in detail with reference to the accompanying drawings, when it is determined that the detailed description of the related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Do it.

3A is a block diagram illustrating a balanced low noise amplifier protected from a transmitter leakage signal according to an exemplary embodiment of the present invention, and FIG. 3B is a diagram illustrating an output change in a frequency domain according to FIG. 3A.

As described with reference to FIGS. 2A and 2B, a circulator 130 is used to share a transmission / reception signal through a single antenna 100 in a base station, an access point, and a repeater of a portable Internet service system using a time division duplex method. In the case of using, the transmit power of several hundred mW or more transmitted from the circulator 130 is applied to the low noise amplifier 110 so that the low noise amplifier is saturated or the internal circuit is destroyed.

In the present invention, in order to prevent the low noise amplifier 110 from being saturated or the internal circuit is destroyed by the leakage signal of the transmission power, a balanced low noise amplifier 200 having a balanced structure characteristic is designed and protected from the leakage signal from the transmitter. 90 ° 3dB hybrids 210 and 210 'are respectively configured at the input and output terminals of the balanced low noise amplifier 200, and two three-stage amplifiers 230 and 230' are configured between the 90 ° 3dB hybrids 210 and 210 '. do. Limiter diodes 220 and 220 'are configured in front of the circuit stages of the first stage amplifiers (low noise transistors, etc.) of the three stage amplifiers 230 and 230' in the balanced low noise amplifier 200, and are transmitted from the limiter diodes 220 and 220 '. It suppresses the leakage signal of power and prevents the power of more than several hundred mW [23dBm (200mW) level] from being applied to the rear stage. It uses the balance structure to reduce the noise figure and reduce the input / output return loss. Implement the property.

The leakage signal of the transmission power input to the balanced low noise amplifier 200 is divided into two branches through the 90 ° 3dB hybrid 210, and after passing through the three-stage amplifiers 230 and 230 'having the same characteristics, 90 ° 3dB again. It is output after being synthesized through the hybrid 210 '. Here, the signals divided by two through the 90 ° 3 dB hybrid 210 of the input stage will have a phase difference of 90 ° to each other. On the other hand, in the 90 ° 3dB hybrid 210 'of the output stage for synthesis, the two signals passing through each of the three stage amplifiers 230 and 230' are already synthesized with a 90 ° phase difference, and consequently in phase at the output stage. Are synthesized.

In terms of gain, since the signal input to the balanced low noise amplifier 200 is divided by 2 through 90 ° 3dB hybrid 210, the power is attenuated by 3dB relative to the input power level, and the signal reduced by 3dB at the output is amplified respectively. 90 ° 3dB hybrid (210 '). The 90 ° 3dB hybrid 210 'of the output stage also has a 3dB attenuation at the output if just one signal is input, but when the output signals are synthesized, the signal is output to the output terminal via the first three stage amplifier 230. Since the signals output to the output terminal through the second three-stage amplifier 230 'have a phase difference of 180 ° with each other and become out of phase, the signals are canceled at the output terminal so that no power output is detected. In other words, when the 90 ° 3dB hybrids 210 and 210 'are distributed and synthesized using the same 90 ° and 3dB hybrids 210 and 210' back and forth, there is no signal loss caused by the 90 ° 3dB hybrids 210 and 210 'itself. . Also, since the outputs of each of the three stage amplifiers 230 and 230 'are in-phase synthesized at the final output, the size of the signal is doubled as it is synthesized, and the 3dB attenuated through the 90 ° 3dB hybrid 210 is completely at the output stage. Is compensated.

The 90 ° 3 dB hybrids 210 and 210 ′ may improve input / output reflection characteristics of the respective amplifiers constituting the first three stage amplifier 230 and the second three stage amplifier 230 ′. First. Assuming that the two three-stage amplifiers 230 and 230 'signals totally reflect outside the pass frequency band, the signal input from the input terminal is compared with the first three-stage amplifier 230 and the second three-stage amplifier 230'. The phase is delayed by 90 ° to be input, and the signal reflected from each of the three stage amplifiers 230 and 230 'is delayed by 90 degrees relative to the first three stage amplifier 230. The input stage 3dB hybrid 210 is returned and synthesized. When the signal entering the input terminal is reflected back from the two three-stage amplifiers 230 and 230 ', respectively, the reflected signal from the second three-stage amplifier 230' passes through 90 ° twice (as it enters and exits). As a result, the signal of the first three-stage amplifier 230 has a total phase difference of 180 °, and these two signals cancel each other out of phase and disappear. Due to this characteristic, even if the reflection characteristic of the amplifier itself is bad, the reflected wave is canceled and disappeared on the input terminal side, and thus the input / output reflection characteristics (VSWR, S11, S22) and the like are greatly improved. Of course, this condition is based on the assumption that the characteristics of the first three-stage amplifier 230 and the second three-stage amplifier 230 'are completely the same, and in general, an amplifier having an equilibrium characteristic uses the same amplifier elements in parallel. do.

In the balanced low-noise amplifier 200 structure, two three stage amplifiers 230 and 230 'are configured to have two stage amplifiers 230 and 230', even though the impedance seen from the first stage amplifier is not matched to 50 kHz. If is equal, the impedance at the 90 ° 3dB hybrid 210 input appears to be matched to the 50 kHz characteristic impedance. This is because the reflected wave does not return to the input due to the characteristics of the 90 ° 3 dB hybrids 210 and 210 ', but is consumed at 50 kHz termination by the sum and difference of phases.

    Even if the limiter diodes 220 and 220 'are additionally configured by using the balanced characteristics, if the two limiter diodes 220 and 220' have the same impedance value, the entire low noise amplifier without a matching circuit may be 50 Ω impedance matched. The transmit power suppressed by the limiter diodes 220 and 220 'causes reflection and is not applied to the circulator 130. Due to the balanced amplifier characteristics, the reflected wave is 50 kHz at the 90 ° 3dB hybrid (210, 210') stage. It is applied by termination and consumed by heat. In this case, the 50Ω termination may be performed using a 50Ω resistor having a capacity corresponding to the reflected wave power.

The limiter diodes 220 and 220 'are linearly output with respect to the input voltage when the input voltage is within the set range, but suppress the output not to exceed the set value when the input voltage exceeds the set range. However, in the circuit using the limiter diodes 220 and 220 ', the blocking voltage is determined by the forward voltage drop (Vf) of the diode, which is almost constant at about 0.6 V, but is slightly changed by the current or the ambient temperature.

When the balanced low noise amplifier 200 according to the present invention is used, intermodulation and tertiary distortion components that may occur in the limiter diodes 220 and 220 'are compared with when the limiter 140 circuit is configured outside the low noise amplifier. Due to the equilibrium structure, the signal is not reflected back to the antenna stage, thereby preventing the signal purity of the transmission signal from deteriorating. If the limiter 140 circuit is configured outside, the limiter diode and the matching circuit should be additionally configured, but the balanced low noise amplifier 200 according to the present invention adds only the limiter diodes 220 and 220 '. The circuit or system can be configured concisely. In addition, since the impedance seen from the 90 ° 3dB hybrid 210 can be designed in the same manner, the low noise amplifier itself has an advantage of being able to be designed without lowering the noise figure and the input / output return loss.

4 is a flowchart of a method for designing a balanced low noise amplifier of a portable Internet time division duplex antenna stage according to the present invention.

Referring to FIG. 4, in the balanced low noise amplifier design method of the portable Internet time division duplex antenna stage according to the present invention, a transmission power of a large output (43 dBm level) is output from a transmitter in a transmission period (S200); In step S210, when the leakage signal of the transmission power is applied to the receiver, the transmission power output from the transmitter is lost (S210), and the limiter diodes 220 and 220 'inside the balanced low noise amplifier 200 are applied to the leakage signal applied to the receiver. Step (S220) of generating a limiter reflected wave combined with intermodulation and tertiary distortion components as it passes, and the 90 ° 3dB hybrid (210, 210 ') ground terminal of the input and output stages configured inside the balanced low noise amplifier 200 The reflected wave power is consumed by the 50 kHz termination, and the input impedance to the balanced low noise amplifier 200 is matched to the 50 Ω characteristic impedance (S230). As the reflected wave power is consumed, the transmit power is reduced. To the original state that is not the cross-modulation, and the third-order distortion component is made by combining such step (S240) the last transmission power radiated from the antenna 100.

The present invention may be modified in various ways without departing from the basic concept according to the needs of those skilled in the art.

As described above, according to the present invention, the receiver low noise amplifier can withstand the leakage signal of the transmit power and the reflected wave power only with a limiter diode added in the low noise amplifier without the implementation of the limiter 140 circuit externally added. The intermodulation and tertiary distortion components generated in the diode are not radiated to the antenna 100. The low noise amplifier design method ensures sufficient signal purity for the final transmission power, thereby providing waveform quality. ) And spectrum mask characteristics are improved, and as there is no need to implement additional limiter circuits externally, concise system design and cost reduction are possible.

Claims (4)

A transmit / receive combined antenna 100, a transmitter power amplifier 120 that radiates transmit power to the outside through the antenna 100, a low noise amplifier of a receiver to which a received signal from the outside is applied through the antenna 100, In the transmission cycle, the power amplifier 120 is turned on and the low noise amplifier is turned off to send out the transmission power. In the reception cycle, the power amplifier 120 is turned on and the power amplifier 120 is turned off. In the low noise amplifier of the antenna stage for providing a mobile Internet service in a time-division duplex method to share the transmission and reception with one antenna by having the circulator 130 (Off) is applied to receive the received signal, The low noise amplifier is formed in a balanced structure with limiter diodes 220 and 220 'therein, which suppress leakage signal of transmission power so that leakage power is not applied to the rear end. A low noise amplifier of a portable Internet time division duplex antenna stage, characterized in that the balanced low noise amplifier (200) to prevent the saturation or the internal circuit is destroyed by the reverse leakage signal applied to the receiving end at the output. The method of claim 1, The balanced low noise amplifier 200, A 90 ° 3 dB hybrid (210, 210 ') of the input and output terminals such that the ground terminal is grounded with a 50 kΩ resistor so that the reflected wave does not return to the input, but is applied to the 50 k termination by the sum and difference of the two signal phases. A first three stage amplifier 230 and a second three stage amplifier 230 'coupled between the 90 ° and 3 dB hybrids 210 and 210' of the input and output terminals, respectively; The 90 ° 3 dB hybrid 210 of the input terminal receives the leakage signal of the transmission power applied to the balanced low noise amplifier 200 through the input terminal, the first three-stage amplifier 230 and the second three-stage amplifier ( 230 ') is divided into two branches so that the signal divided by two has a 90 ° phase difference, and the 90 ° 3 dB hybrid 210' of the output stage is the first three-stage amplifier 230 and the second three-stage amplifier 230 In-phase synthesis of two signals through '), The limiter diodes 220 and 220 'have one end connected to an input terminal of a first stage amplifier of the first three stage amplifier 230 and the second three stage amplifier 230', and the other end is grounded. Low noise amplifier for portable Internet time division duplex antenna stage. The method of claim 2, The first three stage amplifier 230 and the second three stage amplifier 230 'low noise amplifier of the portable Internet time division dual antenna stage, characterized in that consisting of a low noise transistor. In the method of designing a low noise amplifier of the antenna stage to be applied to a base station, an access point, a repeater for providing a mobile Internet service for sharing the transmission and reception with one antenna, In a transmission period, a step (S200) of outputting large transmission power from a transmitting end; A leakage signal of the transmission power is applied to the receiving end so that the transmitting power output from the transmitting end is lost by 20 dB (S210); Generating a limiter reflected wave in which intermodulation and tertiary distortion components are combined as the leakage signal applied to the receiver passes through the limiter diodes 220 and 220 'inside the balanced low noise amplifier 200 (S220); Through the 90 ° 3dB hybrid (210, 210 ') ground terminal of the input and output stages configured inside the balanced low noise amplifier 200, the reflected wave power is consumed by 50 Ω termination, so the input impedance to the balanced low noise amplifier 200 is 50 Ω. Matching the characteristic impedance (S230); As the reflected wave power is consumed, the final transmission power is radiated through the antenna 100 in an original state in which intermodulation and tertiary distortion components are not coupled to transmission power (S240). Low Noise Amplifier Design for Internet Time Division Dual Antenna.

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