Patent Description:
The disclosure further relates to a method of processing radio frequency, RF, signals.

Apparatus for processing RF signals may e.g. be used for processing RF signals that are provided for transmission via an antenna. <CIT> discloses a phase shifter. <CIT> discloses a variable phase shifter. <CIT> discloses a variable phase shifter. <CIT> discloses a phase shifter.

Various embodiments of the disclosure are set out by the independent claims. The exemplary embodiments and features, if any, described in this specification, that do not fall under the scope of the independent claims, are to be interpreted as examples useful for understanding various exemplary embodiments of the disclosure.

Some embodiments feature an apparatus for processing radio frequency, RF, signals, according to claim <NUM>. This enables to process RF signals with increased flexibility, i.e. for distributing RF signals from a source (e.g., a power amplifier) to one or more sinks (e.g., ports of an antenna (system)) and/or influencing a phase of said RF signals.

According to further exemplary embodiments, said apparatus may be used for processing RF signals in a transmitter and/or a transmitter branch of an RF device. According to further exemplary embodiments, said apparatus may be used for processing RF signals in a receiver and/or a receiver branch of an RF device.

According to further exemplary embodiments, said electrically conductive element comprises a port for receiving an input signal, i.e. an RF input signal, which may also be denoted as an input port according to further exemplary embodiments. This way, said electrically conductive element may distribute said input signal to said transmission lines via said capacitive coupling. However, according to further exemplary embodiments, said port of said electrically conductive element may also be configured to output an RF signal, e.g. an RF signal provided to the apparatus at a further port.

According to further exemplary embodiments, at least one of said transmission lines comprises at least one port for output of at least one respective output signal depending on said input signal, which may also be denoted as "output port(s)" according to further exemplary embodiments. As an example, said input signal may be provided to said electrically conductive element, which couples respective portions of said input signal via said capacitive coupling into said transmission lines, and, according to further exemplary embodiments, respective end sections of said transmission lines may comprise ports for providing these signal portions to at least one external device, i.e. an input port of an antenna (system). In this example, said ports may be used as output ports.

However, according to further exemplary embodiments, said at least one port of said at least one transmission line may also be configured to receive an RF signal, e.g. an RF signal provided to the apparatus at said at least one port. According to further exemplary embodiments, said apparatus comprises at least one further transmission line (i.e., three transmission lines), wherein said electrically conductive element is (also) capacitively coupled with said at least one further transmission line, i.e. with all of said three transmission lines.

According to further exemplary embodiments, more than three transmission lines may also be provided, and in these cases, it is also possible that said electrically conductive element is capacitively coupled to a plurality of these more than three transmission lines, or to all of these transmission lines.

According to further exemplary embodiments, said electrically conductive element is translationally movably arranged with respect to all transmission lines. As an example, the transmission lines may be arranged on a (common) carrier element (wherein each of said transmission lines may comprise its own substrate, cf. further below), and said electrically conductive element is translationally movably arranged relative to said carrier element (and thus also relative to all transmission lines). In other words, the electrically conductive element may perform a translatory movement relative to said transmission lines. By moving (manually and/or by means of a drive) said electrically conductive element with respect to the transmission lines, a signal phase of the RF signal coupled from said electrically conductive element into the respective transmission line may be shifted, so that the apparatus according to the embodiments may advantageously be used as a phase shifter for RF signals.

According to further exemplary embodiments, at least one of said transmission lines comprises or is a microstrip line and/or a stripline, which enables a particularly cost effective implementation and reliable operation.

According to further exemplary embodiments, at least two of said transmission lines comprise different properties with respect to at least one of the following elements: a) a relative permittivity of a substrate, b) a geometry. This way, a degree of phase shift effected by the movement of the electrically conductive element relative to the transmission line may be influenced.

As an example, according to further exemplary embodiments, different transmission lines, which may e.g. be provided in the form of microstrip lines, may comprise respective (dielectric) substrates, wherein the relative permittivity of said respective substrates comprises different values.

As a further example, a dielectric substrate of a first transmission line or microstrip line may comprise a first value of said relative permittivity, e.g. <NUM> (e.g., air), whereas a dielectric substrate of a second transmission line or microstrip line may comprise a second, different value of said relative permittivity, e.g. <NUM>.

According to further exemplary embodiments, at least one of said transmission lines may comprise a (preferably low-loss) dielectric material, e.g. a dielectric material a relative permittivity of which may be controlled, e.g. during a manufacturing process. This way, different transmission lines with different properties regarding an effect on the phase shift of an input signal may be obtained according to further exemplary embodiments.

Advantageously, said electrically conductive element comprises at least one impedance transformer, whereby a distribution of signal energy from of the input signal to various branches of said apparatus may be controlled, wherein said branches are characterized by a respective one of said transmission lines.

According to further exemplary embodiments, a conductor of at least one of said transmission lines is embedded into a dielectric substrate, preferably such that it comprises a predetermined distance from a surface of the substrate (i.e., embedding depth) on which e.g. the electrically conductive element may be guided according to further exemplary embodiments. This way, the degree of said capacitive coupling between the electrically conductive element and the respective transmission line may be precisely controlled.

Alternatively, according to further exemplary embodiments, one or more spacers may be provided at said electrically conductive element which may make sliding contact when said electrically conductive element is translationally movedwith respect to said transmission lines. According to further exemplary embodiments, said one or more spacers may comprise dielectric material, so that the spacers may e.g. directly contact a conductor of the transmission line.

Advantageously, at least one of said transmission lines and/or a conductor of at least one of said transmission lines comprises a curved or meandered section. This way, a sensitivity of the phase shift effected by translational movement of the electrically conductive
element with respect to the transmission line(s) may be increased (as compared to a straight, linear transmission line).

According to further exemplary embodiments, said transmission lines are arranged in a same first virtual plane, and said electrically conductive element is arranged within a second virtual plane which is at least substantially parallel (difference of surface normals of said virtual planes less than <NUM> degrees, preferably less than <NUM> degrees) to said first virtual plane.

Further exemplary embodiments relate to an antenna or antenna system comprising at least one apparatus according to the embodiments.

Further exemplary embodiments relate to a use of the apparatus according to the embodiments for applying a phase shift to a radio frequency, RF, signal.

Further exemplary embodiments relate to a method of operating an apparatus for processing radio frequency, RF, signals, wherein said apparatus comprises at least a first transmission line and a second transmission line, and an electrically conductive element that is capacitively coupled with said first transmission line and said second transmission line and that is translationally movably arranged with respect to at least one of said first transmission line and said second transmission line, said method comprising: providing an RF signal as an input signal to said electrically conductive element, and moving said electrically conductive element relative to said at least one of said first transmission line and said second transmission line.

Further exemplary embodiments relate to a use of the apparatus according to the embodiments for distributing an RF input signal to a plurality of sinks while applying a phase shift to said RF input signal.

Further features, aspects and advantages of the illustrative embodiments are given in the following detailed description with reference to the drawings in which:.

<FIG> relate to embodiments that do not include all the features of claim <NUM>. Description of exemplary embodiments.

<FIG> schematically depicts a top view of an apparatus <NUM> according to exemplary embodiments. The apparatus <NUM> may be used for processing radio frequency, RF, signals as explained in detail below.

The apparatus <NUM> comprises at least a first transmission line <NUM> and a second transmission line <NUM>, and an electrically conductive element <NUM> that is capacitively coupled with said first transmission line <NUM> and said second transmission line <NUM>, cf. the first coupling region cr1, where element <NUM> "intersects" (as seen in projection of the top view of <FIG>) a conductor <NUM> of said first transmission line <NUM> and the second coupling region cr2, where element <NUM> "intersects" a conductor <NUM> of said second transmission line <NUM>. In and/or around these "intersections", RF energy may be exchanged between element <NUM> and a respective conductor <NUM>, <NUM> of the transmission lines <NUM>, <NUM>.

Further, said electrically conductive element <NUM> is translationally movably (cf. double arrow m) arranged with respect to at least one of said first transmission line <NUM> and said second transmission line <NUM>, preferably with respect to both transmission lines <NUM>, <NUM>. This enables to process RF signals with increased flexibility, i.e. for distributing RF signals from a source (not shown, e.g., a power amplifier) to one or more sinks (not shown, e.g., ports of an antenna (system)) and/or influencing a phase of said RF signals.

According to further exemplary embodiments, said electrically conductive element <NUM> comprises a port <NUM> for receiving an input signal is, i.e. an RF input signal, wherein said port <NUM> may at least temporarily operate as an input port. This way, said electrically conductive element <NUM> may distribute said input signal is (or respective portions thereof) to said transmission lines <NUM>, <NUM> via said capacitive coupling cr1, cr2. In this respect, an exemplary output signal os is depicted by <FIG> which may be obtained at a first axial end section 110a of said first transmission line <NUM>, said first axial end section 110a exemplarily forming a port <NUM> for signal output of said apparatus <NUM>, wherein said port <NUM> may at least temporarily operate as an output port. Similarly, further output signals (not shown) may be obtained at a second axial end section 110b of the first transmission line <NUM> and at respective axial end sections 120a, 120b of said second transmission line <NUM>.

Moreover, when supplying said input signal is to said input port <NUM>, the phase of respective output signals os may be influenced by moving said electrically conductive element <NUM> with respect to said transmission lines <NUM>, <NUM>, e.g. in a horizontal direction m of <FIG>.

According to further exemplary embodiments, at least one of said transmission lines <NUM> comprises (or constitutes) at least one port <NUM> for output of at least one respective output signal os depending on said input signal is. In this respect, said at least one port <NUM> is exemplarily termed "output port" for the further exemplary explanations. However, according to further exemplary embodiments, apparatus <NUM> may also receive an RF signal at said port <NUM> and/or output an RF signal at said port <NUM>.

As mentioned above, according to exemplary embodiments, said input signal may be provided to said electrically conductive element <NUM> at the input port <NUM>, and the electrically conductive element <NUM> couples respective portions of said input signal is via said capacitive coupling cr1, cr2 into said transmission lines <NUM>, <NUM>, and, according to further exemplary embodiments, respective end sections 110a, 110b, 120a, 120b of said transmission lines <NUM>, <NUM> may comprise output ports <NUM> for providing these signal portions to at least one external device, i.e. an input port <NUM> (<FIG>) of an antenna (system) <NUM>.

In this regard, <FIG> depicts a configuration where the opposing axial end sections 110a, 110b, 120a, 120b of both transmission lines <NUM>, <NUM> are used as output ports, whereby respective output signals os1, os2, os3, os4 may be obtained depending on said input signal is. Note that the phase of the output signals os1, os2, os3, os4 may advantageously be influenced by moving m the element <NUM> with respect to said transmission lines <NUM>, <NUM>.

According to further exemplary embodiments, said electrically conductive element <NUM>, cf. <FIG>, comprises at least one impedance transformer <NUM>, whereby a distribution of signal energy from the input signal is to various branches of said apparatus <NUM> may be controlled, wherein said branches are characterized by a respective one of said transmission lines <NUM>, <NUM>. In other words, by choosing parameters of the impedance transformer <NUM>, a distribution of energy of said input signal is to said transmission lines <NUM>, <NUM> may be controlled.

According to further exemplary embodiments, at least one of said transmission lines <NUM>, <NUM> comprises or is a microstrip line, which enables a particularly cost effective implementation and reliable operation.

<FIG> schematically depicts a top view of an apparatus 100a according to further exemplary embodiments. In these embodiments, the impedance transformer <NUM> is exemplarily implemented in form of a contour discontinuity (presently effected by a stepwise change of the width along a longitudinal axis) of the electrically conductive element <NUM>.

<FIG> schematically depicts a side view of an apparatus 100b according to further exemplary embodiments. It can be seen that the first transmission line <NUM> (cf. <FIG>) comprises a substrate <NUM> (<FIG>) and a conductor <NUM> arranged on a top surface of said substrate <NUM>. Similarly, the second transmission line <NUM> (<FIG>) comprises a substrate <NUM> (<FIG>) and a conductor <NUM> arranged on a top surface of said substrate <NUM>.

According to further exemplary embodiments, the electrically conductive element <NUM> comprises one or more spacers <NUM> which may make sliding contact with said surface of the substrate(s) <NUM>, <NUM> when said electrically conductive element <NUM> is translationally moved with respect to said transmission lines <NUM>, <NUM> (perpendicular to the drawing plane of <FIG>).

According to further exemplary embodiments, said one or more spacers <NUM> may comprise dielectric material, so that the spacers may e.g. directly contact a conductor <NUM>, <NUM> of the transmission line(s) <NUM>, <NUM>. This is exemplarily depicted by the dashed rectangle <NUM>' of <FIG>. , according to further exemplary embodiments, at least one spacer <NUM>' may be provided alternatively or additionally to the spacer(s) <NUM>. Spacer <NUM>' may e.g. be used to provide mechanical support to the electrically conductive element <NUM> and/or capacitance adjustment between components <NUM>, <NUM>. According to some embodiments, spacer <NUM>' may be attached to the electrically conductive element <NUM>.

According to further exemplary embodiments, the transmission lines <NUM>, <NUM> (or their substrate(s) <NUM>, <NUM>) may be arranged on a (common) carrier element <NUM>, and said electrically conductive element <NUM> may be translationally movably arranged relative to said carrier element <NUM> (and thus also relative to all transmission lines). By moving said electrically conductive element with respect to the transmission lines, a signal phase of the RF signal coupled from said electrically conductive element <NUM> into the respective transmission line <NUM>, <NUM> may be shifted, so that the apparatus according to the embodiments may advantageously be used as a phase shifter for RF signals is, os, especially also as a phase shifter for multiband and/or wideband operation.

According to further exemplary embodiments, the optional carrier <NUM> may also form a ground plane or generally an electrically conductive surface a predetermined electrical (reference) potential, such as ground potential, may be applied to.

<FIG> schematically depicts a side view of an apparatus 100c according to further exemplary embodiments. In these exemplary embodiments, a conductor <NUM>, <NUM> of at least one of said transmission lines <NUM>, <NUM> is embedded into the dielectric substrate <NUM>, <NUM>, preferably such that it comprises a predetermined distance from a surface 122a of the substrate (i.e., embedding depth) on which e.g. the electrically conductive element <NUM> may be guided according to further exemplary embodiments. This way, the degree of said capacitive coupling between the electrically conductive element <NUM> and the respective transmission line <NUM>, <NUM> may be precisely controlled, and the conductors <NUM>, <NUM> are protected from environmental influences.

Further exemplary embodiments relate to a method of operating an apparatus according to the embodiments, said method comprising, cf. the flow chart of <FIG>: providing <NUM> an RF signal as an input signal is (<FIG>) to said electrically conductive element <NUM>, and moving <NUM> (<FIG>) said electrically conductive element <NUM>, also cf. double arrow m of <FIG>, relative to said at least one of said first transmission line <NUM> and said second transmission line <NUM>.

According to further exemplary embodiments, said apparatus 100d, cf. the top view of <FIG>, comprises at least one further transmission line <NUM>', i.e., three transmission lines <NUM>', <NUM>', <NUM>', wherein said electrically conductive element <NUM> is (also) capacitively coupled with said at least one further transmission line <NUM>', i.e. with all of said three transmission lines <NUM>', <NUM>', <NUM>'.

Returning to <FIG>, the first transmission line <NUM>' comprises two output ports P1, P6 characterized by respective axial end sections of said transmission line <NUM>', the second transmission line <NUM>' also comprises two output ports P2, P5 characterized by respective axial end sections of said transmission line <NUM>', and the third transmission line <NUM>' also comprises two output ports P3, P4 characterized by respective axial end sections of said transmission line <NUM>'. In other words, an input signal is provided to the input port P7 at the electrically conductive element <NUM> of the apparatus 100d of <FIG> may be distributed to said six output ports P1, P2, P3, P4, P5, P6.

The above explanation of the ports P1,. , P7 exemplarily considers using the ports P1,. , P6 at least temporarily as output ports and port P7 at least temporarily as input port. However, according to further exemplary embodiments, any of said ports P1,. , P7 may be used for receiving and/or transmitting respective RF signal(s). As a further example, ports P1,. , P6 may be used as input ports, i.e. for receiving a plurality of respective RF signals (i.e., from different antenna elements of an RF antenna), and port P7 may be provided to output an RF signal depending on said plurality of RF input signals received at said input ports P1,. For the further exemplary explanations, however, it is referred to cases where said input signal is is provided to port P7 and is distributed via the apparatus 100d to the ports P1,. , P6 with a respective phase shift.

According to further exemplary embodiments, the electrically conductive element <NUM> comprises three different sections 140a, 140b, 140c, wherein width discontinuities between adjacent sections 140a, 140b; 140b, 140c implement a respective impedance transformer 142a, 142b that controls energy distribution between said transmission lines <NUM>', <NUM>', <NUM>' via said electrically conductive element <NUM>.

According to further exemplary embodiments, at least two of said transmission lines <NUM>', <NUM>', <NUM>' (<FIG>) comprise different properties with respect to at least one of the following elements: a) a relative permittivity of a substrate <NUM>, <NUM>, <NUM>, b) a geometry (e.g., width of the conductor(s). This way, a degree of phase shift effected by the movement of the electrically conductive element <NUM> relative to the transmission line may be influenced.

As a further example, a dielectric substrate <NUM> of a first transmission line <NUM>' or microstrip line may comprise a first value of said relative permittivity, e.g. <NUM> (e.g., air), whereas a dielectric substrate <NUM> of a second transmission line <NUM>' or microstrip line may comprise a second, different value of said relative permittivity, e.g. <NUM>, and a dielectric substrate <NUM> of a third transmission line <NUM>' or microstrip line may comprise a third, different value of said relative permittivity, e.g. <NUM>. Similar observations also apply to the embodiments of <FIG>.

According to further exemplary embodiments, at least one of said transmission lines <NUM>', <NUM>', <NUM>' (<FIG>) may comprise a (preferably low-loss) dielectric material <NUM>, <NUM>, <NUM>, particularly a dielectric material a relative permittivity of which may be selected and/or controlled, e.g. during a manufacturing process. This way, different transmission lines <NUM>', <NUM>', <NUM>' with different properties regarding an effect on the phase shift of an input signal may be obtained according to further exemplary embodiments.

According to further exemplary embodiments, at least one of said transmission lines and/or a conductor of at least one of said transmission lines comprises a curved or meandered section, cf. conductor <NUM> of <FIG>. This way, a sensitivity of the phase shift effected by translational movement of the electrically conductive element <NUM> with respect to the transmission line(s) <NUM>' may be increased (as compared to a straight, linear transmission line <NUM>', <NUM>').

According to further exemplary embodiments, said electrically conductive element <NUM> extends with its longitudinal axis perpendicularly to a respective longitudinal axis of at least one transmission line (which is e.g. horizontal in <FIG>). According to further exemplary embodiments, a direction of said translatory movement m (<FIG>) of said electrically conductive element <NUM> is parallel to a respective longitudinal axis of at least one transmission line.

According to further exemplary embodiments, said transmission lines <NUM>', <NUM>', <NUM>' are arranged in a same first virtual plane, and said electrically conductive element <NUM> is arranged within a second virtual plane which is at least substantially parallel (difference of surface normals of said virtual planes less than <NUM> degrees, preferably less than <NUM> degrees) to said first virtual plane.

<FIG> each schematically depict a top view of the apparatus 100d according to <FIG> in a different operational state. In <FIG>, the electrically conductive element <NUM>, which may also be denoted as "slider", is in a first (presently, left) position pos1 with reference to a coordinate axis x, which is horizontal in <FIG>. In <FIG>, the slider <NUM> is in a second (presently, middle) position pos2, and in <FIG>, the slider <NUM> is in a third (presently, right) position. According to further exemplary embodiments, the slider <NUM> may also be moved to further positions not depicted by <FIG>, e.g. intermediate positions between pos1, pos or pos2, pos3, or further positions, e.g. "beyond" pos1 or pos <NUM>.

<FIG> schematically depicts a return loss (magnitude) over frequency f (in an exemplary frequency range between <NUM> and <NUM>) for the apparatus 100d of <FIG> according to further exemplary embodiments, wherein curve RL1 corresponds to the "left" slider position pos1 of <FIG>, wherein curve RL2 corresponds to the "middle" slider position pos2 of <FIG>, and wherein curve RL3 corresponds to the "right" slider position pos3 of <FIG>.

<FIG>, <FIG> each schematically depict scattering parameters (forward gain, magnitude) S<NUM>,<NUM> , S<NUM>,<NUM>,. , S<NUM>,<NUM> over frequency f (in an exemplary frequency range between <NUM> and <NUM>) for different operational states pos1, pos2, pos3 of the apparatus 100d according to <FIG>, wherein <FIG> corresponds to the "left" slider position pos1 of <FIG>, wherein <FIG> corresponds to the "middle" slider position pos2 of <FIG>, and wherein <FIG> corresponds to the "right" slider position pos3 of <FIG>.

<FIG>, <FIG> each schematically depict a phase of scattering parameters (forward gain) S<NUM>,<NUM> , S<NUM>,<NUM>,. , S<NUM>,<NUM> over frequency f (in an exemplary frequency range between <NUM> and <NUM>) for different operational states of the apparatus 100d according to <FIG>, wherein <FIG> corresponds to the "left" slider position pos1 of <FIG>, wherein <FIG> corresponds to the "middle" slider position pos2 of <FIG>, and wherein <FIG> corresponds to the "right" slider position pos3 of <FIG>.

<FIG>, <FIG> each schematically depicts an antenna characteristic (gain over vertical angle θ) as obtained by different operational states of the apparatus 100d according to <FIG>, when using the apparatus 100d for supplying respective input ports <NUM> (<FIG>) of an antenna system <NUM> with phase shifted output signals as may be obtained at the output ports P1, P2, P3, P4, P5, P6 of the apparatus 100d, cf. <FIG> when supplying an RF input signal is to the input port P7. In this regard, the antenna characteristic of <FIG> corresponds to a first state of the slider <NUM> (<FIG>), the antenna characteristic of <FIG> corresponds to a second state of the slider <NUM> (<FIG>), and the antenna characteristic of <FIG> corresponds to a third state of the slider <NUM> (<FIG>). It can be seen that by moving the slider <NUM> into different states, the so obtained phase shift of output signals provided at the output ports P1 to P6 of the apparatus 100d may advantageously be used for antenna beam pattern control of an antenna system, presently e.g. for controlling a downtilt angle.

In this regard, <FIG> schematically depicts a simplified block diagram of an antenna <NUM> according to further exemplary embodiments. A phase shifter apparatus 100d (also cf. <FIG>) according to exemplary embodiments is provided at its input port P7 with an input signal is and distributes the signal energy of the input signal is via the elements <NUM>, <NUM>', <NUM>', <NUM>' (<FIG>) to its output ports P1 to P6 (also cf. reference numeral P' of <FIG>) for forwarding to the antenna system's <NUM> input port <NUM>, e.g. via six discrete RF transmission lines or cables.

According to further exemplary embodiments, the apparatus <NUM>, 100a, 100b, 100c, 100d may also be integrated into an antenna or antenna system <NUM>.

Further exemplary embodiments relate to a use of the apparatus according to the embodiments for applying a phase shift to a radio frequency, RF, signal is, os.

Further exemplary embodiments relate to a use of the apparatus according to the embodiments for distributing an RF input signal is (<FIG>) to a plurality of sinks P1 to P6 while applying a phase shift to said RF input signal is and/or a signal derived therefrom, e.g. by moving the slider <NUM> with respect to the transmission lines <NUM>', <NUM>', <NUM>'.

According to further exemplary embodiments, insertion losses in dB as low as <NUM> at a frequency of <NUM>, <NUM> at a frequency of <NUM> and <NUM> at a frequency of <NUM> could be attained by using the apparatus 100d.

According to further exemplary embodiments, mechanical dimensions of said apparatus 100d (<FIG>) when designed for an operation with input signals in a frequency range of about <NUM> (Gigahertz) to about <NUM> are about <NUM> (millimeter) (width, as e.g. seen in <FIG>) x <NUM> (height, <FIG>). In other words, the principle according to the embodiments enables to provide compact apparatus for distributing and/or phase shifting of RF input signals is.

The apparatus described herein may be configured to operate in one or more operational frequency bands. For example, the operational frequency bands may include (but are not limited to): Long Term Evolution (LTE) (US) (<NUM> to <NUM> and <NUM> to <NUM>), Long Term Evolution (LTE) (rest of the world) (<NUM> to <NUM> and <NUM> to <NUM>), amplitude modulation (AM) radio (<NUM>-<NUM>); frequency modulation (FM) radio (<NUM>-<NUM>); Bluetooth (<NUM>-<NUM>); wireless local area network (WLAN) (<NUM>-<NUM>); hiper local area network (HiperLAN) (<NUM>-<NUM>); global positioning system (GPS) (<NUM>-<NUM>); US - Global system for mobile communications (US-GSM) <NUM> (<NUM>-<NUM>) and <NUM> (<NUM> - <NUM>); European global system for mobile communications (EGSM) <NUM> (<NUM>-<NUM>) and <NUM> (<NUM> - <NUM>); European wideband code division multiple access (EU-WCDMA) <NUM> (<NUM>-<NUM>); personal communications network (PCN/DCS) <NUM> (<NUM>-<NUM>); US wideband code division multiple access (US-WCDMA) <NUM> (transmit: <NUM> to <NUM>, receive: <NUM> to <NUM>) and <NUM> (<NUM>-<NUM>); wideband code division multiple access (WCDMA) <NUM> (transmit: <NUM>-<NUM>, receive: <NUM>-<NUM>); personal communications service (PCS) <NUM> (<NUM>-<NUM>); time division synchronous code division multiple access (TD-SCDMA) (<NUM> to <NUM>, <NUM> to <NUM>), ultra wideband (UWB) Lower (<NUM>-<NUM>); UWB Upper (<NUM>-<NUM>); digital video broadcasting - handheld (DVB-H) (<NUM>-<NUM>); DVB-H <CIT> MHz); digital radio mondiale (DRM) (<NUM>-<NUM>); worldwide interoperability for microwave access (WiMax) (<NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>); digital audio broadcasting (DAB) (<NUM>-<NUM>, <NUM>-<NUM>); radio frequency identification low frequency (RFID LF) (<NUM>-<NUM>); radio frequency identification high frequency (RFID HF) (<NUM>-<NUM>); radio frequency identification ultra high frequency (RFID UHF) (<NUM>, <NUM>-<NUM>, <NUM>); frequency allocations for <NUM>, for example <NUM> to <NUM> and/or <NUM> to <NUM>.

Further aspects and advantages that may at least partly be attained with at least some exemplary embodiments are: simple structure (efficient and cost-effective manufacturing), very stable return loss over different states (cf. <FIG>), possibility to achieve very high amount of phase shifting, relatively small in size, easy to tune, wideband solution, low insertion loss.

Claim 1:
Apparatus (<NUM>; 100a; 100b; 100c; 100d) for processing radio frequency, RF, signals, wherein said apparatus (<NUM>; 100a; 100b; 100c; 100d) comprises at least a first transmission line (<NUM>; <NUM>') and a second transmission line (<NUM>; <NUM>'), and an electrically conductive element (<NUM>) that is capacitively coupled (cr1, cr2) with said first transmission line (<NUM>; <NUM>') and said second transmission line (<NUM>; <NUM>') and that is translationally movably (m) arranged with respect to at least one of said first transmission line (<NUM>; <NUM>') and said second transmission line (<NUM>; <NUM>'), wherein said electrically conductive element (<NUM>) comprises at least one impedance transformer (<NUM>; 142a, 142b), wherein the at least one impedance transformer (<NUM>; 142a, 142b) is implemented in form of a contour discontinuity of the electrically conductive element (<NUM>), wherein at least one of said transmission lines and/or a conductor (<NUM>) of at least one of said transmission lines (<NUM>') comprises a curved or meandered section.