CN219227597U

CN219227597U - Tower top amplifier

Info

Publication number: CN219227597U
Application number: CN202190000399.7U
Authority: CN
Inventors: M·蒂霍宁; Y·A·埃里克森; H·海斯卡拉
Original assignee: Kailaisi Co
Current assignee: Kailaisi Co
Priority date: 2020-04-01
Filing date: 2021-03-23
Publication date: 2023-06-20
Anticipated expiration: 2031-03-23
Also published as: WO2021197922A1; SE2251113A1

Abstract

In accordance with one or more embodiments of the present disclosure, a Tower Mounted Amplifier (TMA) (100) is provided that is configured to receive a duplex Radio Frequency (RF) signal. The TMA (100) comprises: a first port (110) configured to receive a Tx signal and output an Rx signal; a second port (120) configured to receive an Rx signal and output a Tx signal; an RF power harvester (150) arranged to generate a DC voltage and/or DC current from the Tx signal received on the first port (110); and at least one amplifier (130), such as a Low Noise Amplifier (LNA), arranged to amplify the signal received on the second port (120) during transmission of the signal to the first port (110).

Description

Tower top amplifier

Technical Field

The present disclosure relates generally to a Tower Mounted Amplifier (TMA) configured to receive duplex Radio Frequency (RF) signals.

Background

The tower top amplifier is typically installed in the base station tower. The transmit power from the base station tower is typically very high so that the RF signal from the base station antenna can reach mobile phones far from the base station tower with higher signal quality. However, the RF signals received by the base station antennas typically have a relatively low power, since the mobile phone itself does not have a very high transmit power. Furthermore, since the antenna is mounted on top of the base station tower, and the actual base station is typically located further down the base station tower, the cable between the two will introduce losses. Thus, the signal received by the base station antenna must be amplified, for example using TMA, to overcome this loss.

Time Division Duplexing (TDD) uses a single frequency channel to transmit signals in both the transmit (Tx) and receive (Rx) directions by transmitting signals in different time slots. TDD operates by switching transmission directions at high speed during time intervals. In order to support the use of a single frequency channel, TDD typically requires a quiet time interval between transmitting and receiving data streams.

US20190296792 describes a TDD signal booster that amplifies signals in two directions in different ways.

US6812786 describes a zero bypass switching circuit using a mismatched 90 ° hybrid coupler.

US10523260 describes a base station antenna having a transmitter and a receiver therein supporting TDD with enhanced bias control for high speed switching.

The inventors of the present utility model have noted that at least the problems described below exist in the prior art, for example.

The purpose of TMA is to amplify the signal received by the base station antenna. However, if the amplifier in the TMA is sized to amplify the RF signal (Rx signal) received by the base station antenna, the RF signal (Tx signal) transmitted by the base station antenna may be strong enough that if they reach the amplifier, a malfunction occurs because the Tx signal is much stronger than the Rx signal. Therefore, when the TDD signal is received in the TMA, it is necessary to prevent the Tx signal from reaching the amplifier.

US20190296792 discloses a control circuit which detects silence intervals and controls an amplifier circuit to change configuration so that signals in both directions are amplified in different ways. However, if the power difference between the signals in the two directions is large, such control may not be sufficient to protect the amplifier.

US6812786 describes a zero bypass switching circuit using a mismatched 90 ° hybrid coupler and biased PIN diode. In such a solution it has to be ensured that there is a DC voltage and/or a DC current available for biasing the diode. Furthermore, the arrangement described in US6812786 will not be able to handle very strong Tx signals without damaging the amplifier components, thus using a duplex filter to separate the Tx signal from the Rx signal. And it is not possible to use such a duplex filter for TDD signals.

There is therefore a need for improved TMAs.

Disclosure of Invention

The above problem is solved by the claimed TMA arranged for receiving duplex RF signals. TMA may include: a first port configured to receive a Tx signal and output an Rx signal; a second port configured to receive an Rx signal and output a Tx signal; an RF power harvester arranged to generate a DC voltage and/or DC current from the signal received on the first port; and at least one amplifier arranged to amplify the signal received at the second port before outputting it on the first port. The second port is preferably connected to a base station antenna.

In an embodiment, the generated DC voltage and/or DC current is used to feed a component within the TMA, which component is preferably used to prevent RF signals received on the first port from reaching the at least one amplifier. Such a component may be, for example, a diode that is biased, for example, using a negative voltage generated by the RF power harvester.

In an embodiment, the TMA includes a function for detecting power received on the first port, for example, using an RF power harvester.

In an embodiment, the TMAs comprise short circuit points arranged to short circuit any RF signal that does not flow to the second port when power is detected on the first port, such that the signal is reflected instead of reaching the at least one amplifier. The shorting point may be, for example, any RF signal that is arranged to not flow through a switching device in the TMA.

In an embodiment, a PIN diode is used to short the short point and the resulting DC voltage and/or DC current is used to bias the PIN diode.

In an embodiment, the TMA comprises a switching arrangement. The switching means may be arranged to prevent a signal received on the first port from reaching the at least one amplifier when power is detected on the first port.

In an embodiment, the switching device is arranged to: when power is detected on the first port, being arranged to allow a signal received on the first port to flow directly to the second port through the switching means without passing through the at least one amplifier; and when no power is detected on the first port, is arranged to prevent the signal received on the second port from flowing through the switching means in the process of reaching the first port, so that the signal received on the second port is fed to the at least one amplifier, allowing the at least one amplifier to amplify the signal received on the second port before outputting it on the first port. The second port is preferably connected to a base station antenna.

In an embodiment, the TMA comprises at least one circulator arranged to prevent any signal received on the first port from reaching the at least one amplifier. If any part of the Tx signal received on the first port does not flow through the switching means, for example due to leakage through the isolated port of the hybrid coupler, the circulator will ensure that the Tx signal cannot reach the at least one amplifier in any way.

In an embodiment, the switching device comprises a combination of a hybrid coupler and/or circulator and one or more PIN diodes, and the generated DC voltage and/or DC current is used to bias the one or more PIN diodes in the switching device. The one or more PIN diodes may be, for example, biased to short various shorting points in the switching device.

The above problems are further addressed by the disclosed solution for generating a DC voltage and/or DC current in a TMA arranged to receive duplex RF signals. The scheme may include: receiving a Tx signal on a first port; generating a DC voltage and/or DC current from the signal received on the first port, for example using an RF power harvester; receiving an Rx signal on the second port; amplifying the signal received on the second port; and outputting the amplified signal on a first port. The second port is preferably connected to a base station antenna.

In an embodiment, the arrangement comprises means for feeding a component within the TMA using the generated DC voltage and/or DC current, the means preferably being for preventing RF signals received on the first port from reaching the at least one amplifier. Such a component may be, for example, a diode that is biased, for example, using a negative voltage generated by the RF power harvester.

In an embodiment, the scheme includes detecting power on the first port, for example, using an RF power harvester.

In an embodiment, the arrangement comprises, when power is detected on the first port, shorting any RF signal that does not flow to the second port at a shorting point such that the signal is reflected instead of reaching the at least one amplifier. The short-circuit point may be, for example, any RF signal that is arranged to short-circuit without flowing through the switching devices in the TMA.

In an embodiment, the scheme includes using the generated DC voltage and/or DC current to bias a PIN diode for shorting the shorting point.

In an embodiment, the arrangement comprises, when power is detected on the first port, preventing as much as possible of the signal received on the first port from reaching the at least one amplifier using the switching means.

In an embodiment, the scheme includes: when power is detected on the first port, the switching means is arranged to allow a signal received on the first port to flow directly through the switching means to the second port without passing through the at least one amplifier; and when no power is detected on the first port, the switching means is arranged to prevent the signal received on the second port from flowing through the switching means during its arrival at the first port, such that the signal received on the second port is fed to the at least one amplifier, allowing the at least one amplifier to amplify the signal received on the second port before outputting it on the first port.

In an embodiment, the scheme includes using at least one circulator to prevent any signal received on the first port from reaching the at least one amplifier. If any part of the Tx signal received on the first port does not flow through the switching means, for example due to leakage through the isolated port of the hybrid coupler, the circulator will ensure that the Tx signal cannot reach the at least one amplifier anyway.

In an embodiment, the switching device comprises a combination of a hybrid coupler and/or circulator and one or more PIN diodes, and the scheme comprises biasing the one or more PIN diodes in the switching device with the generated DC voltage and/or DC current. The one or more PIN diodes may be, for example, biased to short various shorting points in the switching device.

In an embodiment, TMA is a time division multiplexed TMA (TDD-TMA).

The scope of the utility model is defined by the claims, which are incorporated into this section by reference. A more complete understanding of embodiments of the present utility model will be afforded to those skilled in the art, as well as a realization of additional advantages thereof, by a consideration of the following detailed description of one or more embodiments. Reference will first be made to a brief description of the drawings.

Drawings

Fig. 1-7 schematically illustrate various embodiments of TMAs configured to receive duplex RF signals in accordance with one or more embodiments described herein.

Fig. 8 schematically illustrates an embodiment of an RF power harvester according to one or more embodiments described in the present disclosure.

Fig. 9 schematically illustrates a scheme 900 for generating a DC voltage and/or DC current in TMA 100 configured to receive duplex RF signals in accordance with one or more embodiments described herein.

Embodiments of the present disclosure and their advantages are best understood by referring to the detailed description that follows. It should be understood that like reference numerals are used to identify like elements illustrated in one or more of the figures.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

The present disclosure relates generally to a Tower Mounted Amplifier (TMA) configured to receive a duplex Radio Frequency (RF) signal. Embodiments of the disclosed solution are shown in more detail in connection with the accompanying drawings.

Fig. 1-7 schematically illustrate various embodiments of a TMA 100 configured to receive duplex RF signals in accordance with one or more embodiments described herein. The various TMA 100 embodiments schematically illustrated in fig. 1-7 each include a first port 110 and a second port 120. The second port 120 is preferably connected to a base station antenna arranged to transmit Tx signals and to receive Rx signals. The TMA further comprises at least one amplifier 130, such as a low noise amplifier (LNA, low Noise Amplifier), arranged to amplify the Rx signal received from the antenna of the second port 120 and transmitted to the first port 110, which Rx signal is output at the first port 110.

Since the at least one amplifier 130 is preferably sized for amplifying the Rx signal, if the Tx signal reaches the at least one amplifier 130, the Tx signal may be strong enough to cause a malfunction because the Tx signal is much stronger than the Rx signal. It is therefore desirable to prevent the Tx signal from reaching the at least one amplifier 130.

The various TMA 100 embodiments schematically illustrated in fig. 1-7 each include an RF power harvester 150 configured to generate a DC voltage and/or DC current from the Tx signal received on the first port 110. The generated DC voltage and/or DC current may be, for example, components for feeding into TMA 100, such as various components for preventing Tx signals received on first port 110 from reaching at least one amplifier 130. RF power harvester 150 may, for example, generate a negative DC voltage that may be used to bias diodes in TMA 100. In this case, the diode in TMA 100 may also be biased when no external DC voltage is available, which means that intermodulation will be much better than diode "floating".

The RF power harvester 150 may also be used to detect power received on the first port 110 because DC voltage and/or DC current can only be generated when power is on the first port 110. Since detecting power on the first port 110 means that a Tx signal is being received in the TMA 100, this may be used to control the TMA 100 to send the Tx signal to the second port 120, which may be sent to the antenna at the second port 120 while preventing the Tx signal from reaching the at least one amplifier 130. Such control is preferably achieved by controlling components within TMA 100, such as by forward or reverse biasing diodes in TMA 100.

The various TMA 100 embodiments schematically illustrated in fig. 1-6 each include a shorting point 160, which shorting point 160 may be used to short any RF signal that does not flow to the second port 120 so that the signal is reflected instead of reaching the at least one amplifier 130. To ensure that no Tx signal arrives at the at least one amplifier 130, the shorting point 160 may be controlled to short when power is detected on the first port 110. In the TMA 100 embodiment schematically illustrated in fig. 1-3 and 5, the shorting point 160 is shorted by the forward biased PIN diode 165 and the resulting DC voltage and/or DC current is used to forward bias the PIN diode 165.

The various TMA 100 embodiments schematically illustrated in fig. 1-7 each include a switching arrangement 140, which switching arrangement 140 is operable to prevent Tx signals received on the first port 110 from reaching the at least one amplifier 130. To ensure that no Tx signal reaches the at least one amplifier 130, when power is detected on the first port 110, the switching device 140 may be controlled to prevent the Tx signal received on the first port 110 from reaching the at least one amplifier 130.

In the TMA 100 embodiment schematically illustrated in fig. 1, 2 and 7, the switching arrangement 140 comprises a combination of

hybrid couplers

181, 182 and a PIN diode 195. The PIN diode 195 in the switching device 140 may be biased using the generated DC voltage and/or DC current, for example.

Hybrid couplers are four-port devices that can split an incident power signal into two output ports. The phase difference between the two output ports of the hybrid coupler may be 0 °, 90 ° or 180 °, depending on the type used. The

hybrid couplers

181, 182 are preferably 90 ° hybrid couplers, wherein the signals at the outputs have a phase difference of 90 ° with respect to each other. Reflections due to mismatch are sent to the isolated port, preventing any power from reflecting back to the input port.

The loss of the PIN diode depends on the line impedance. By utilizing the possibility of transforming the impedance with an impedance transforming hybrid coupler, such as the one described in US8174338, the losses of the PIN diode can be minimized.

In TMA 100 schematically shown in fig. 1, PIN diode 195 is reverse biased when power is detected on first port 110 such that shorting point 190 does not short, which allows Tx signals received on first port 110 to flow through switching device 140 to second port 120 for further transmission to the antenna without passing through at least one amplifier 130. However, when no power is detected on the first port 110, the PIN diode 195 is forward biased, shorting the shorting point 190 such that the Rx signal is reflected and sent through the amplifier 130 via the isolated port of the hybrid coupler 182 without being allowed to flow through the hybrid coupler 181. In this way, the Rx signal received from the antenna on the second port 120 is prevented from flowing through the switching means 140 during reaching the first port 110, while the Rx signal is fed to the at least one amplifier 130, thereby allowing the at least one amplifier 130 to amplify the Rx signal received on the second port 120 and then output it on the first port 110.

In TMA 100, schematically shown in fig. 2, PIN diode 195 is forward biased when power is detected on first port 110, allowing Tx signals received on first port 110 to flow through switching device 140 to second port 120 for further transmission to the antenna without passing through at least one amplifier 130. However, when no power is detected on the first port 110, the PIN diode 195 is reverse biased such that the Rx signal is reflected and sent through the amplifier 130 via the isolated port of the hybrid coupler 182, but is not allowed to flow through the hybrid coupler 181. In this way, the Rx signal received from the antenna on the second port 120 is prevented from flowing through the switching means 140 during reaching the first port 110, while the Rx signal is fed to the at least one amplifier 130, thereby allowing the at least one amplifier 130 to amplify the Rx signal received on the second port 120 and then output it on the first port 110.

In the various TMA 100 embodiments schematically illustrated in fig. 3-6, switching arrangement 140 includes a combination of

circulators

171, 172 and PIN diode 195. The PIN diode 195 in the switching device 140 may be biased using the generated DC voltage and/or DC current, for example.

In the TMA 100 embodiment schematically illustrated in fig. 3 and 4, PIN diode 195 is forward biased when power is detected on first port 110, allowing Tx signals received on first port 110 to flow through switching device 140 to second port 120 for further transmission to the antenna without passing through at least one amplifier 130. However, when no power is detected on the first port 110, the PIN diode 195 is reverse biased such that the Rx signal is reflected and sent through the amplifier 130 via the circulator 172 without being allowed to flow through the circulator 171. In this way, the Rx signal received from the antenna on the second port 120 is prevented from flowing through the switching means 140 during reaching the first port 110, while the Rx signal is fed to the at least one amplifier 130, thereby allowing the at least one amplifier 130 to amplify the Rx signal received on the second port 120 and then output it on the first port 110.

In the TMA 100 embodiment schematically illustrated in fig. 5 and 6, PIN diode 195 is reverse biased when power is detected on first port 110 such that shorting point 190 is not shorted, which allows Tx signals received on first port 110 to flow through switching device 140 to second port 120 for further transmission to the antenna without passing through at least one amplifier 130. However, when no power is detected on the first port 110, the PIN diode 195 is forward biased, shorting the shorting point 190 so that the Rx signal is reflected and passed through the amplifier 130 via the circulator 172 without being allowed to flow through the circulator 171. In this way, the Rx signal received from the antenna on the second port 120 is prevented from flowing through the switching means 140 during reaching the first port 110, while the Rx signal is fed to the at least one amplifier 130, thereby allowing the at least one amplifier 130 to amplify the Rx signal received on the second port 120 and then output it on the first port 110.

In the TMA 100 embodiment schematically shown in fig. 1-6, tx signals received on the first port 110 are allowed to flow through the switching means 140 to the second port 120 for further transmission to the antenna. In these embodiments, at least one amplifier 130 is disposed outside of the switching device 140.

The TMA 100 embodiment schematically shown in fig. 1 and 2 further comprises a circulator 170, which circulator 170 is arranged to prevent any Tx signal received on the first port 110 from flowing to the at least one amplifier 130 without flowing through the switching means 140. If any portion of the Tx signal received on the first port 110 were to leak through the isolated port of the hybrid coupler 181 and thus not flow through the switching device 140, the circulator 170 would ensure that the signal would not reach the at least one amplifier 130 in any way. The additional protection provided by the circulator 170 is beneficial in that the amplifier 130 cannot withstand Tx power until the diode 165 shorts the shorting point 160, even for a short period of time. However, using an amplifier 130 that can withstand Tx power for a short time interval, no circulator 170 is required.

In TMA 100 schematically shown in fig. 7, switching means 140 includes a combination of

hybrid couplers

181, 182, circulator 170 and PIN diode 195, and two amplifiers 130 are provided within switching means 140. The PIN diode 195 in the switching device 140 may be biased using the generated DC voltage and/or DC current, for example. When power is detected on the first port 110, the PIN diode 195 is forward biased, shorting the shorting point 190, causing the Tx signal to be reflected and sent through the isolated port of the first hybrid coupler 181 to the second hybrid coupler 182, and then reflected again and sent through the isolated port of the second hybrid coupler 182 to the second port 120 for further transmission to the antenna. In this way, the Tx signal received on the first port is prevented from reaching the amplifier 130. However, when no power is detected on the first port 110, the PIN diode 195 is reverse biased such that the shorting point 190 is not shorted, and this allows the Rx signal received on the second port 120 to flow through the amplifier 130 to the first port 110, thereby allowing the amplifier 130 to amplify the Rx signal received on the second port 120 before outputting it on the first port 110.

In TMA 100 schematically shown in fig. 7, the Tx signal received on first port 110 is thus prevented from flowing through switching arrangement 140. In this embodiment, at least one amplifier 130 is disposed inside the switching device 140.

TMA 100 schematically shown in fig. 7 further comprises a circulator 170, which circulator 170 is arranged to prevent any Tx signal received on first port 110 from flowing to amplifier 130. If any portion of the Tx signal received on the first port 110 leaks through the shorting point 190, the circulator 170 will ensure that it cannot reach the at least one amplifier 130 anyway.

Fig. 8 schematically illustrates an embodiment of an RF power harvester 150 arranged to generate a DC voltage and/or DC current on the

output ports

810, 820 from the Tx signal. The RF power harvester 150, schematically shown in fig. 8, basically acts as an envelope detector, providing an output on

output ports

810, 820 as an envelope of the Tx signal. The schematic circuits in fig. 8 may be cascaded to obtain higher DC voltages and/or DC currents.

As shown in fig. 8, RF power harvester 150 can couple a portion of the Tx power into forward coupled lines and a portion into reverse coupled lines, e.g., such that the reverse coupled lines provide output on output port 810 and the forward coupled lines provide output on output port 820. Thus a DC voltage and/or DC current may be generated on both

outputs

810, 820, but the RF power harvester 150 may also be arranged to generate a DC voltage on one of the

outputs

810, 820 and a DC current on the other of the

outputs

810, 820.

An RF probe may be used instead of coupling a portion of the Tx power to the forward and reverse coupled lines, but in this case there is a risk that the reflected power can cancel the forward power. In cases where both DC voltage and DC current are required, the RF power may be split to feed the RF power to the DC voltage converter and the DC current converter.

The RF power harvester 150 may also be used to detect that a Tx signal is being received in the TMA 100. This may be used to control TMA 100 to divert Tx signals to second port 120, send them to the antenna in second port 120, while preventing Tx signals from reaching at least one amplifier 130. The control is preferably accomplished by using the generated DC voltage and/or DC current to control components within TMA 100, for example, by forward or reverse biasing diodes in TMA 100. In this case, the diode in TMA 100 may also be biased when no external DC voltage or current is available, meaning that intermodulation will be much better than diode "floating". RF power harvester 150 may, for example, generate a negative DC voltage that may be used to bias diodes in TMA 100.

The utility model is particularly useful when TMA is time division multiplexed TMA (TDD-TMA).

Fig. 9 schematically illustrates a scheme 900 for generating a DC voltage and/or DC current in TMA 100 configured to receive duplex RF signals in accordance with one or more embodiments of the present utility model. Scheme 900 may include:

step 910: the Tx signal is received on the first port 110.

Step 920: a DC voltage and/or DC current is generated from the signal received on the first port 110, for example, using the RF power harvester 150.

Step 940: the Rx signal is received on the second port 120.

Step 950: amplifies the signal received on the second port 120.

Step 960: the amplified signal is output on the first port 110.

Scheme 900 may also include at least one of:

step 925: the generated DC voltage and/or DC current is used to feed components within TMA 100. Such a component may be, for example, a diode, which is biased, for example, using a negative voltage generated by the RF power harvester.

Step 930: the power on the first port 110 is detected, for example, using an RF power harvester 150.

Step 970: when power is detected on the first port 110, any RF signal that does not flow to the second port 120 is shorted in the shorting point 160 so that the signal is reflected instead of reaching the at least one amplifier 130.

Step 975: the generated DC voltage and/or DC current is used to bias the PIN diode 165 for shorting the shorting point 160.

Step 980: when power is detected on the first port 110, the switching means 140 is used to prevent as much as possible the signal received on the first port 110 from reaching the at least one amplifier 130.

Step 985: when power is detected on the first port 110, the switching means 140 is arranged to allow the signal received on the first port 110 to flow through the switching means 140 directly to the second port 120 without passing through the at least one amplifier 130, and when no power is detected on the first port 110, the switching means 140 is arranged to prevent the signal received on the second port 120 from flowing through the switching means 140 during arrival at the first port 110 so that the signal received on the second port 120 is fed to the at least one amplifier 130, allowing the at least one amplifier 130 to amplify the signal received on the second port 120 before outputting it on the first port 110.

Step 990: at least one circulator 170 is used to prevent any signal received on the first port 110 from reaching the at least one amplifier 130. If any portion of the Tx signal received on the first port 110 does not flow through the switching device 140, for example, due to leakage through the isolated port of the hybrid coupler 181, the circulator 170 will ensure that the Tx signal cannot reach the at least one amplifier 130 in any way.

In an embodiment, the switching device 140 comprises a combination of

hybrid couplers

181, 182 and/or

circulators

170, 171, 172 and one or more PIN diodes 195, and the scheme comprises using the generated DC voltage and/or DC current for biasing the one or more PIN diodes 195 in the switching device 140. One or more PIN diodes 195 may be biased, for example, to cause various shorting points in the switching device 140 to be shorted.

In an embodiment, TMA 100 is a time division multiplexed TMA (TDD-TMA).

The foregoing disclosure is not intended to limit the utility model to the precise form or particular field of use disclosed. Various alternative embodiments and/or modifications of the present utility model, whether explicitly described or implied in the disclosure, are possible in light of this disclosure. The TMA embodiments described in this disclosure all include many different components that are configured to prevent Tx signals from reaching the amplifier and, of course, not all of these different components need be provided in TMA 100. A simpler TMA embodiment having only some of the described functions can be readily set by those skilled in the art based on the TMA embodiments described in this disclosure. Accordingly, the scope of the utility model is limited only by the claims.

Claims

1. A tower top amplifier, TMA, (100) arranged for receiving duplex Radio Frequency (RF) signals, the TMA (100) comprising:

a first port (110) configured to receive a Tx signal and output an Rx signal;

a second port (120) configured to receive an Rx signal and output a Tx signal;

an RF power harvester (150) arranged to generate a DC voltage and/or DC current from a signal received on the first port (110); and

at least one amplifier (130) arranged to amplify the signal received on the second port (120) before outputting it on the first port (110);

wherein the generated DC voltage and/or DC current is used to feed components within the TMA (100) for preventing RF signals received on the first port (110) from reaching the at least one amplifier (130).

2. The TMA (100) of claim 1, wherein the TMA (100) comprises a function of detecting power received on the first port (110).

3. The TMA (100) of claim 2, wherein the TMA (100) comprises a shorting point (160), the shorting point (160) being arranged to short any RF signal not flowing to the second port (120) such that the RF signal is reflected instead of reaching the at least one amplifier (130) when power is detected on the first port (110).

4. A TMA (100) according to claim 3, wherein a PIN diode (165) is used to short the short circuit point (160), the resulting DC voltage and/or DC current being used to bias the PIN diode (165).

5. The TMA (100) of any of claims 2-4, wherein the TMA (100) comprises a switching means (140), wherein the switching means (140) is arranged to prevent a signal received on the first port (110) from reaching the at least one amplifier (130) when power is detected on the first port (110).

6. The TMA (100) of claim 5, wherein the switching means (140) is arranged to:

when power is detected on the first port (110), being arranged to allow a signal received on the first port (110) to flow directly to the second port (120) through the switching means (140) without passing through the at least one amplifier (130); and

when no power is detected on the first port (110), it is arranged to prevent a signal received on the second port (120) from flowing through the switching means (140) in the process of reaching the first port (110), such that the signal received on the second port (120) is fed to the at least one amplifier (130), allowing the at least one amplifier (130) to amplify (110) the signal received on the second port (120) before outputting it on the first port.

7. The TMA (100) of claim 5, wherein the TMA (100) comprises at least one circulator (170), the circulator (170) being arranged to prevent any signal received on the first port (110) from reaching the at least one amplifier (130).

8. TMA (100) according to claim 5, wherein the switching means (140) comprises a combination of hybrid couplers (181, 182) and/or circulators (170, 171, 172) and one or more PIN diodes (195), and the generated DC voltage and/or DC current is used to bias the one or more PIN diodes (195) in the switching means (140).

9. The TMA (100) of any of claims 1-4, wherein said TMA is a time division multiplexed TMA (TDD-TMA).

10. The TMA (100) of claim 2, wherein the TMA (100) comprises a function of detecting power received on the first port (110) using the RF power harvester (150).