This includes integrated circuits of matched filter networks and corresponding matched filter methods.

Abstract

This invention relates to an integrated circuit having a power amplifier (PA), an antenna (ANT), and an adaptive filter network (MFN), the power amplifier (PA) being used to provide a signal in a baseband, the integrated circuit comprising: a first part (SCT1), a second part (SCT2), and a third part (SCT3); these three parts include an LC arrangement configured to have an impedance adapted to the output of the power amplifier (PA) in the baseband, wherein the LC arrangement of the first part (SCT1) and the second part (SCT2) is further configured to have resonant frequencies respectively suitable for attenuating harmonic bands of the baseband.

Description

Technical Field

[0001] The embodiments and implementations relate to integrated circuits that include matched filter networks, which are typically located between the output of a power amplifier and an antenna. Background Technology

[0002] On the one hand, a power amplifier operates at maximum efficiency when the load at its output is at its optimal impedance. The optimal impedance at the power amplifier output is typically different from the impedance of the antenna to which it is connected.

[0003] Therefore, impedance matching circuitry is typically provided between the output of a power amplifier and the antenna to convert the antenna's impedance to the amplifier's ideal impedance. Impedance matching circuitry is usually formed using passive components such as resistors, inductors, and capacitors. Impedance matching circuitry can occupy a potentially large surface area, which can be particularly disadvantageous when forming impedance matching circuitry within small integrated circuits.

[0004] On the other hand, the emission spectrum of a power amplifier often contains interfering signals, such as harmonic frequencies of the fundamental frequency or noise generated due to the internal nonlinearity of the power amplifier.

[0005] As a result, a filter circuit is typically provided between the output of the power amplifier and the antenna to filter two frequency bands, especially harmonics, such as up to the fifth order. The filter circuit is usually formed using passive components such as resistors, inductors, and capacitors, and also occupies a potentially large surface area, which is particularly disadvantageous when impedance matching circuits are formed in an integrated manner.

[0006] Impedance matching and filtering circuits have specific constraints and are usually designed separately.

[0007] While techniques that separate these two functions (impedance matching and filtering) are satisfactory in terms of performance, they require a large number of passive components, which are expensive and cumbersome to manufacture.

[0008] However, reducing the size of integrated circuits reduces the surface area available for passive devices, making it more difficult to integrate these two functions at a satisfactory performance level.

[0009] While using surface acoustic wave (SAW) filters reduces the required space, it increases the cost.

[0010] Therefore, there is a need for a compact and inexpensive solution that can achieve impedance matching and filtering while achieving good performance levels. Summary of the Invention

[0011] According to embodiments and implementations, the present invention proposes providing impedance matching and filtering in a single network, wherein impedance matching is provided by a network with the minimum quality factor to achieve optimal response over the widest possible frequency range while keeping the number of passive components as small as possible; filtering is provided by replacing passive components with a rationally selected inductor-capacitor arrangement to resonate at the frequency to be filtered without modifying the impedance transformation in the transmission frequency. Specifically, the resonant frequency of the inductor-capacitor arrangement is selected to optimize the network size and response.

[0012] In this regard, one aspect proposes an integrated circuit comprising a power amplifier, an antenna, and a matched filter network, wherein the power amplifier is used to provide a signal in the baseband, and the matched filter network includes:

[0013] - The first part between the output node of the power amplifier and the first intermediate node

[0014] -The second part between the first intermediate node and the second intermediate node, and

[0015] - The third part between the second intermediate node and the input node of the antenna.

[0016] These three sections comprise an inductor-capacitor "LC" arrangement configured to have an impedance that matches the output of the power amplifier in the fundamental frequency band. The LC arrangements of the first and second sections are also configured to have resonant frequencies, respectively suitable for attenuating the harmonic bands of the fundamental frequency band.

[0017] For convenience, and according to conventional use in electronics, the symbol "LC" is used to denote the term "inductor-capacitor".

[0018] Therefore, a matched filter network with three LC arrangement parts is proposed, wherein all LC arrangements in the first and second parts are configured for both impedance matching and harmonic frequency filtering.

[0019] In particular, it should be noted that all LC arrangements in each of the first and second parts are configured for simultaneous matching and filtering functions, unlike conventional techniques where one arrangement is dedicated to matching and another arrangement (at least partially separate) is dedicated to filtering.

[0020] The third part is dedicated to impedance matching, and in particular, is not configured to have a resonant frequency in order to maintain high-frequency attenuation.

[0021] Therefore, a design based on this aspect proposes to fully integrate the matching and filtering functions into the LC arrangement of the first and second parts, allowing for the formation of a particularly compact integrated circuit without sacrificing performance or increasing cost.

[0022] According to one embodiment, the LC arrangement of the first portion is configured to have a resonant frequency lower than that of the corresponding LC arrangement of the second portion.

[0023] More specifically, for impedance matching, the capacitor element on the power amplifier side in the first part is typically larger than the capacitor element on the antenna side in the second part. On the other hand, the resonant frequency of an LC arrangement is inversely proportional to the size of the inductor and capacitor elements in the LC arrangement. Therefore, this embodiment proposes to optimize the resonant frequency for the size of the inductor element provided for filtering. Thus, the overall space requirement is optimized to be as low as possible.

[0024] According to one embodiment, the first part includes a parallel LC arrangement coupled between the output node of the power amplifier and a first intermediate node, and a series LC arrangement coupled between the first intermediate node and a ground node; the second part includes a parallel LC arrangement coupled between the first intermediate node and a second intermediate node, and a series LC arrangement coupled between the second intermediate node and a ground node.

[0025] Therefore, a parallel LC arrangement blocks the signal at its resonant frequency, while a series LC arrangement routes the signal at its resonant frequency to ground.

[0026] According to one embodiment, each series LC arrangement is configured to have an equivalent impedance corresponding to the impedance of a capacitor element suitable for impedance matching in the fundamental frequency band, and wherein the resonant frequency of each series LC arrangement is selected to be distributed in two frequency bands of different harmonics of the fundamental frequency band, and such that the series LC arrangement whose equivalent impedance corresponds to the impedance of the capacitor element with the smallest capacitance value has the largest resonant frequency.

[0027] In other words, the resonant frequency of the series LC arrangement in the first and second parts is selected by combining the smallest inductor element with the capacitor element for impedance matching.

[0028] More specifically, since the value of the inductor required to make the capacitor resonate is inversely proportional to the capacitance value and the square of the resonant frequency, the highest resonant frequency is advantageously associated with the lowest capacitance value in order to minimize the value of the inductor to be added.

[0029] This embodiment again proposes to optimize the overall space requirements by positioning the resonant frequency in a way that is optimized for the size of the sensing element, thereby achieving filtering functionality in each of the first and second parts.

[0030] According to one embodiment, the resonant frequencies of each parallel LC arrangement are selected such that they, together with the resonant frequencies of the series LC arrangement, are distributed in different harmonic bands of the fundamental frequency band.

[0031] Therefore, by combining the capacitive element with the inductive element provided for impedance matching, the resonant frequency is located within the harmonic frequency band still to be filtered. This embodiment allows filtering on both frequency bands of all harmonics.

[0032] More specifically, since inductors typically occupy more space than capacitors, the location of the resonant frequency with capacitance in a parallel LC arrangement results in an additional space requirement of an acceptable order of magnitude compared to the space required for the equivalent inductance provided for impedance matching, and compared to the space saved by the inductance in an optimized series LC filter.

[0033] According to one embodiment, the LC arrangement of the first part and the second part is configured according to at least one of the following criteria:

[0034] - The parallel LC arrangement of the first part is configured to have a resonant frequency in half of the second harmonic frequency band;

[0035] - The parallel LC arrangement of the second part is configured to have a resonant frequency in the other half of the second harmonic frequency band;

[0036] - The series LC arrangement of the first part is configured to have a resonant frequency in the third harmonic band;

[0037] - The second part of the series LC arrangement is configured to have a resonant frequency between the fourth harmonic band and the fifth harmonic band, or in the common part of the fourth harmonic band and the fifth harmonic band.

[0038] This embodiment provides the possibility of locating the resonant frequency to optimize overall space requirements and the possibility of achieving optimal performance.

[0039] In particular, attention should be paid to the location of the resonant frequency of the first part of the series LC arrangement in the third harmonic frequency band, rather than in the upper half of the second harmonic frequency band. This location advantageously prevents potential coupling problems between the resonant frequency of the first part of the parallel LC arrangement (in the second harmonic frequency band) and the resonant frequency of the first part of the series LC arrangement (not in the second harmonic frequency band).

[0040] According to one embodiment, the third part includes an LC arrangement comprising an inductive element coupled between the second intermediate node and the input node of the antenna, and a capacitive element coupled between the input node of the antenna and the ground node, the LC arrangement of the third part being configured to have a minimum quality factor.

[0041] According to another aspect, the present invention proposes a method for impedance matching and filtering between the output of a power amplifier and an antenna, the power amplifier providing a signal in the baseband, the method comprising dimensioning a virtual matching network comprising:

[0042] - The first part between the output node of the power amplifier and the first intermediate node

[0043] -The second part between the first intermediate node and the second intermediate node, and

[0044] -The third part between the second intermediate node and the antenna input node,

[0045] Each of the three parts includes inductive and capacitive elements, and the dimensions are configured to have an impedance that matches the output of the power amplifier in the baseband.

[0046] The method includes forming a real matched filter network, which involves replacing each inductor and each capacitor element of the first and second portions of the virtual matched network with respective “LC” inductor-capacitor arrangements configured to have an equivalent impedance that matches the output of a power amplifier in the baseband, and also having resonant frequencies that are respectively suitable for attenuating harmonic bands of the baseband.

[0047] Based on this approach, a dimensioning method for virtual impedance matching networks is proposed, which does not provide filtering functionality, in order to dimension the impedance matching requirements.

[0048] For example, the term "virtual" is understood to mean "existing only in a state of possibility or chance, but not in a state of material realization," especially intermediate computation.

[0049] The filtering is then introduced into a real (i.e., the opposite of "virtual") matched filter network, which actually exists to match and filter the transmitted signal. This real matched filter network is obtained by replacing the virtual components with real components that are equivalent to the impedance matching requirements and additionally have filtering functions.

[0050] In practice, for any embodiment of the power amplifier and antenna, this method allows for the complete integration of matching and filtering functions into the LC arrangement of the first and second parts in a compact, efficient, and inexpensive manner.

[0051] According to one embodiment, the resonant frequency of the LC arrangement of the first part of the real matched filter network is selected to be lower than the resonant frequency of the corresponding LC arrangement of the second part of the real matched filter network.

[0052] According to one embodiment, a first portion of the virtual matching network includes an inductor coupled between the output node of the power amplifier and a first intermediate node, and a capacitor coupled between the first intermediate node and a ground node. A second portion of the virtual matching network includes an inductor coupled between the first intermediate node and a second intermediate node, and a capacitor coupled between the second intermediate node and a ground node. The formation of the real matched filter network includes replacing each inductor with a parallel LC arrangement and replacing each capacitor with a series LC arrangement.

[0053] According to one embodiment, the resonant frequency of each series LC arrangement is first selected to be distributed in different harmonic bands of the fundamental frequency band, and the series LC arrangement that replaces the capacitor element of the virtual matching network with the minimum capacitance value has the maximum resonant frequency.

[0054] According to one embodiment, the resonant frequencies for each parallel LC arrangement are then selected such that they, together with the resonant frequencies of the series LC arrangement, are distributed in different harmonic bands of the fundamental frequency band.

[0055] According to one embodiment, a real matched filter network is formed based on at least one of the following criteria:

[0056] - The parallel LC arrangement of the first part has a resonant frequency in half of the second harmonic frequency band;

[0057] -The parallel LC arrangement of the second part has a resonant frequency in the other half of the second harmonic frequency band;

[0058] -The series LC arrangement of the first part has a resonant frequency in the third harmonic band;

[0059] - The second part of the series LC arrangement has a resonant frequency between the fourth harmonic band and the fifth harmonic band, or in the common part of the fourth harmonic band and the fifth harmonic band. Attached Figure Description

[0060] After examining the detailed description of the non-limiting embodiments and implementations, and from the accompanying drawings, other advantages and features of the invention will become clear, wherein:

[0061] Figures 1 to 5 Examples and implementations of the present invention are shown. Detailed Implementation

[0062] Figure 1 The diagram illustrates a matched filter network MFN between the output node of the power amplifier PA and the input node of the antenna ANT, for example, integrated into an integrated circuit.

[0063] The power amplifier (PA) is configured to provide a transmission signal in the baseband, particularly suitable for radio frequency (RF) communication such as 4G, 5G or LTE, Wi-Fi or Bluetooth communication.

[0064] The matched filter network MFN consists of three matched and filtered sections SCT1, SCT2, and SCT3, as well as a DC power supply stage DCFD.

[0065] The DC power supply stage DCFD includes an inductor connected in series between the power supply voltage terminal VCC and the power amplifier output node, and a capacitor between the power supply voltage terminal VCC and the ground reference voltage terminal GND.

[0066] The DC power supply stage (DCFD) allows the voltage level and current required for the matching filter network (MFN) to be supplied from the output node of the power amplifier (PA).

[0067] The first part SCT1 is located between the output node of the power amplifier PA and the first intermediate node N1, the second part SCT2 is located between the first intermediate node N1 and the second intermediate node N2, and the third part SCT3 is located between the second intermediate node N2 and the input node of the antenna ANT.

[0068] Each of the three parts SCT1, SCT2, and SCT3 includes inductor and capacitor elements, i.e., an inductor-capacitor arrangement, which is usually referred to as an "LC" arrangement for convenience.

[0069] The LC arrangement of the three sections SCT1, SCT2 and SCT3 is configured to have an impedance that matches the output of the power amplifier PA in the baseband.

[0070] The impedance is matched to the output of the power amplifier PA because at this impedance, the optimal power of the transmitted signal is delivered from the power amplifier PA to the antenna ANT, especially to ensure that the power reflection of the transmitted signal is minimized.

[0071] Furthermore, the LC arrangement of the first part SCT1 and the second part SCT2 is configured to have resonant frequencies that are respectively suitable for attenuating the harmonic frequency band of the fundamental frequency band.

[0072] Harmonic frequencies are integer multiples of the fundamental frequency of the transmitted signal.

[0073] Specifically, the first part SCT1 includes a parallel LC arrangement 11 coupled between the output node of the power amplifier PA and the first intermediate node N1, and a series LC arrangement 12 coupled between the first intermediate node N1 and the ground node GND.

[0074] Similarly, the second part SCT2 includes a parallel LC arrangement 21 coupled between the first intermediate node N1 and the second intermediate node N2, and a series LC arrangement 22 coupled between the second intermediate node N2 and the ground node GND.

[0075] The third part, SCT3, includes an inductive element coupled between the second intermediate node N2 and the input node of the antenna ANT, and a capacitive element coupled between the input node of the antenna ANT and ground GND.

[0076] The LC arrangement in the third section is configured to have a minimum quality factor, meaning it is not intended to provide filtering at the resonant frequency, but allows attenuation to be maintained at high and ultra-high frequencies. The LC arrangement in the third section is dedicated to impedance matching.

[0077] It should be noted that a coupling capacitor CC is typically provided between the input node of the antenna ANT and the antenna to block the DC component of the voltage, and its capacitance value is chosen to be large enough to have a negligible effect on impedance matching.

[0078] Therefore, the parallel LC arrangement 11, 21 will prevent the signal at its resonant frequency from being transmitted from the output of the power amplifier PA to the antenna ANT via the intermediate nodes N1, N2 through the series channel.

[0079] In addition, the series LC arrangement 12, 22 routes the signal at its resonant frequency from the output of the power amplifier PA to the antenna ANT, and through intermediate nodes N1, N2 to ground GND (commonly referred to as a shunt).

[0080] According to an advantageous example embodiment, each parallel LC arrangement 11, 21 is configured in a dual manner to have, on the one hand, a function for use in the baseband ( Figure 2 The equivalent impedance corresponding to the impedance of the inductor element used for impedance matching in the above impedance matching, on the other hand, has two harmonic frequency bands ( Figure 5 The resonant frequencies f11 and f21 selected from one of them are... Figure 5 ).

[0081] Similarly, each cascaded LC arrangement 12, 22 is advantageously configured in a dual manner, on the one hand, having features suitable for use in the baseband ( Figure 2 The equivalent impedance corresponding to the impedance of the capacitor element used for impedance matching in the above impedance matching, and having two harmonic frequency bands ( Figure 5 The resonant frequencies f12 and f22 are selected from one of them. Figure 5 ), used to reduce the inductance of a series LC arrangement to the equivalent impedance.

[0082] In particular, it should be noted that each LC arrangement 11, 12, 21, 22 of the first part SCT1 and the second part SCT2 is configured as a whole for both impedance matching and filtering functions. That is, there are no components in the LC arrangements of the first part SCT1 and the second part SCT2 that are specifically used for impedance matching or filtering functions.

[0083] refer to Figures 2 to 4 To show the reference above Figure 1 This describes an advantageous method for dimensioning the inductor and capacitor components of an impedance-matched filter network (MFN).

[0084] Figure 2 A virtual matching network MN0 is shown, which will serve as a reference benchmark for comparison with the reference network. Figure 1 The inductors and capacitors of the matched filter network MFN are dimensioned.

[0085] The matching network MN0 is described as "virtual" because it is used solely for computational purposes to determine the magnitude of the impedance matching requirement. The results of the dimensioning will serve as the computational basis for evaluating the actual resulting components, in conjunction with a reference... Figure 1 The described network MFN implements matching and filtering.

[0086] The virtual matching network MN0 consists of three virtual matching parts SCT01, SCT02, SCT03 and a DC power supply stage DCFD.

[0087] The three virtual parts SCT01, SCT02, and SCT03 are similar in structure to the third part SCT3. That is, they each include an inductor on a series path from the output node of the power amplifier PA to the input node of the antenna ANT via intermediate nodes N1 and N2, and a capacitor on the intermediate nodes N1, N2 and the input node of the antenna ANT, coupled in parallel to ground GND.

[0088] Therefore, the virtual matching network MN0 corresponds to the low-pass network with the smallest quality factor among the three parts SCT01, SCT02, and SCT03, and is provided to match the impedance between the output of the power amplifier PA and the antenna ANT.

[0089] Now for reference Figure 3 .

[0090] Figure 3 The Smith chart is shown, normalized by the impedance of the antenna ANT, so that the impedance of the antenna ANT is located at the center of the Smith chart.

[0091] The dimensioning is performed in such a way that the impedance of the antenna RANT is converted to the ideal impedance of the power amplifier RPA.

[0092] Therefore, the intermediate impedances R1 and R2 are calculated using the geometric mean between the antenna impedance RANT and the ideal impedance RPA presented at the output node of the power amplifier PA.

[0093] in other words:

[0094] R1=(RA 2 xRL) 1 / 3

[0095] R2=(RAxRL 2 ) 1 / 3

[0096] Strictly speaking, the calculation is performed using RPA, which is the inverse of the real part of the admittance presented at the output node of the power amplifier PA, and RANT, which is the inverse of the real part of the admittance of the antenna ANT.

[0097] The intermediate impedances R1 and R2 correspond to the impedances (strictly speaking, the inverse of the real part of the admittance) that will be presented at the intermediate nodes N1 and N2 of the virtual matching network MN0.

[0098] By reading the Smith chart and by referencing Figure 4 The defined equations EQ1 and EQ2 yield each part SCT01, SCT02, SCT03 (or SCTk-) Figure 4 The values ​​of capacitor C0 and inductor L0.

[0099]

[0100]

[0101] Where ω is the angular frequency at a selected frequency (f0) from the fundamental frequency band, R L It is the impedance (strictly speaking, the inverse of the real part of the admittance) presented to the left of each part SCTk (k∈[01; 02; 03]), R G It is the impedance presented on the right side of each part of SCTk (strictly speaking, the inverse of the real part of the admittance), such as Figure 4 As shown.

[0102] The imaginary part of the admittance of the load at the output node of the power amplifier PA is generated by the inductor of the DC power supply stage DCFD, through which the power amplifier PA is powered.

[0103] As referenced above Figure 1 The method then includes forming a real matched filter network MFN in each part SCT01, SCT02, SCT03 of the virtual matched network MN0 according to inductor L0 and capacitor C0 elements that are thus dimensioned.

[0104] In this regard, refer to Figure 1 and Figure 2 .

[0105] The formation of the actual matched filter network MFN involves replacing each inductor element and each capacitor element of the first portion SCT01 and the second portion SCT02 of the virtual matching network MN0 with their respective resonant inductor-capacitor "LC" arrangements. The inductor-capacitor "LC" arrangements are configured to have an impedance equivalent to the matching impedance of the virtual matching network MN0 in the fundamental frequency band, and also to have resonant frequencies suitable for attenuating the harmonic bands of the fundamental frequency band.

[0106] Specifically, the inductor L0 of the virtual matching network MN0 is replaced by parallel LC arrangements 11 and 12, which have the same impedance and corresponding resonant frequency f at a frequency f0 selected within the fundamental frequency band. r .

[0107] For each section SCT1, SCT2, the inductance L and capacitance C of the components in the parallel LC arrangement 11, 21 are given by equations EQ3 and EQ4.

[0108] EQ3:

[0109] EQ4:

[0110] Where L0 is the inductance value of the inductor element that is replaced in each part SCT01 and SCT02, f0 is the frequency in the fundamental band, and f r It is the resonant frequency of the corresponding parallel LC arrangement.

[0111] Furthermore, specifically, the capacitor element C0 of the virtual matching network MN0 is replaced by series LC arrangements 12 and 22, which have the same impedance at a frequency f0 selected within the fundamental frequency band, and at the corresponding resonant frequency f r There is resonance at that point.

[0112] For each section SCT1, SCT2, the capacitance C and inductance L of the series LC arrangement 12, 22 components are given by equations EQ5 and EQ6.

[0113] EQ5:

[0114] EQ6:

[0115] Where C0 is the capacitance value of the capacitor element that is replaced in each part SCT01 and SCT02 respectively, f0 is the frequency in the fundamental band, f r It is the resonant frequency of the corresponding parallel LC arrangement.

[0116] Resonant frequency f r The harmonic band selected as the attenuation fundamental frequency band.

[0117] Now for reference Figure 5 .

[0118] Figure 5 As shown in the reference Figure 1 The above and reference Figures 2 to 4 The obtained matched filter network MFN has a favorable positioning of the resonant frequencies (fr)f11, f12, f21, f22.

[0119] Curve 51 shows the transmission gain of the matched filter network MFN, curve 52 shows the transmission gain of the network MFN in the baseband FB, curve 53 shows the real part of the impedance of the network MFN in the baseband FB, and curve 54 shows the imaginary part of the impedance of the network MFN in the baseband FB.

[0120] The resonant frequency of the parallel LC arrangement 11 of the first part SCT1 is denoted as f11, the resonant frequency of the series LC arrangement 12 of the first part SCT1 is denoted as f12, the resonant frequency of the parallel LC arrangement 21 of the second part SCT2 is denoted as f21, and the resonant frequency of the series LC arrangement 22 of the second part SCT2 is denoted as f22 (reference). Figure 1 Different resonant frequencies will be directly referenced through their respective references.

[0121] In a favorable example, the resonant frequency f11 is located at half (e.g., the lower half) of the second harmonic band HB2.

[0122] The resonant frequency f12 is located in the third harmonic band HB3.

[0123] The resonant frequency f21 is located in the other half (e.g., the upper half) of the second harmonic frequency band HB2.

[0124] The resonant frequency f22 is located between the fourth harmonic band HB4 and the fifth harmonic band HB5, that is, in the case where the fourth and fifth harmonic bands HB4 and HB5 overlap, it is located in the common part of the bands HB4 and HB5.

[0125] On the one hand, this provides more than 38 dB of attenuation at the second harmonic band HB2, and more than 40 dB of attenuation at all other harmonics.

[0126] Furthermore, this example corresponds to a spatially optimized implementation of the matched filter network MFN.

[0127] More specifically, it is assumed that in this type of embodiment, the inductor has a much larger size and occupies much more space than the capacitor; it is assumed that the capacitor C0 coupled to the ground in the virtual matching network MN0 has a lower value near the antenna ANT and a higher value near the power amplifier PA; and it is assumed that the value of the inductor required to make the capacitor resonate is inversely proportional to the square of the capacitance value and the resonant frequency; and the number of inductors added to make the capacitor coupled to the ground resonate should be minimized.

[0128] Therefore, the minimum capacitance value C0 is primarily related to the maximum resonant frequency, which in this case is between the fourth harmonic band HB4 and the fifth harmonic band HB5. This will minimize the value of the inductor L, which is determined by equation EQ6 of the series LC arrangement 22 of the second part SCT2.

[0129] Then, the capacitive element of the first part SCT01 of the virtual network MN0 is selected to resonate in the highest harmonic frequency band (i.e., the third harmonic frequency band HB3) that has not yet been filtered. This will minimize the value of the inductor L determined by equation EQ6 of the series LC arrangement 12 of the first part SCT1, while additionally covering the third harmonic frequency band HB3.

[0130] Therefore, the two sensing elements of the series LC arrangement 12, 22 of the two parts SCT1 and SCT2 require a minimum total space, while having resonant frequencies distributed in a manner suitable for attenuating multiple harmonic frequency bands HB3, HB4, HB5 respectively.

[0131] The resonant frequencies of the parallel LC arrangement 11 and the T-shaped LC arrangement 30 can be more freely located in the remaining harmonic band HB2 because the additional space required by the added capacitor elements is smaller than that required by the inductor elements, especially compared to the space savings achieved by optimizing the inductor elements of the series LC arrangements 12, 22.

[0132] Then the resonant frequencies f11 and f21 are selected to be distributed in the second harmonic frequency band HB2, for example, the resonant frequencies f11 and f21 in each half of the frequency band HB2.

[0133] In order to maintain a certain degree of attenuation at high frequencies, the inductor and capacitor elements of the third part SCT3 are not replaced by a resonant LC arrangement.

[0134] In summary, the resonant frequencies f22 and f12 of each series LC arrangement are first selected to be distributed in different harmonic bands of the fundamental frequency band, and the series LC arrangement with the capacitor element replacing the virtual matching network with the minimum capacitance value has the maximum resonant frequency.

[0135] Then, for each parallel LC arrangement 11, 21, the resonant frequency is selected and distributed together with the resonant frequency of the series LC arrangement 12, 22 in different harmonic bands of the fundamental frequency band.

[0136] Curve 52 shows that the maximum loss in the baseband FB is approximately 1.6 dB.

[0137] Curves 53 and 54 show that the real part of the impedance is contained in the range of approximately 10% (e.g., 4.5 ohms), while the imaginary part is contained in the range of approximately 15 pF (picofarads).

[0138] Therefore, a matching and filtering technique that is advantageous in terms of size and performance is described, with a very inexpensive arrangement of passive components.

[0139] In summary, matching is performed by a low-pass filter with three parts having the minimum quality factor in order to provide impedance transformation of the real part.

[0140] The imaginary part of the optimal impedance of a power amplifier is generated by the inductor in the DC power supply stage.

[0141] A capacitive coupling element is added before the antenna to block the DC voltage. Its value is chosen to be large enough to have a small effect on impedance transformation.

[0142] Harmonic suppression (filtering) is achieved by replacing series inductors with parallel LC arrangements and parallel capacitors with series LC arrangements. The equivalent reactance of the LC arrangement is kept equal to the reactance of the respective replaced elements in the fundamental frequency band.

[0143] The resonant frequency of the LC arrangement is advantageously chosen as follows:

[0144] - A first parallel LC arrangement on the output side of the power amplifier blocks the top portion of the second harmonic frequency band;

[0145] - The first parallel LC circuit blocks the bottom portion of the second harmonic frequency band;

[0146] - The first parallel-series LC arrangement on the output side of the power amplifier releases frequencies in the third harmonic band;

[0147] - The second parallel-series LC arrangement releases frequencies in the fourth and fifth harmonic bands.

[0148] - The inductor and capacitor elements at the very end of the antenna side are not replaced by the resonant circuit in order to provide attenuation for higher-order harmonics, i.e., greater than the 5th order.

Claims

1. An integrated circuit comprising a power amplifier (PA), an antenna (ANT), and a matched filter network (MFN), said power amplifier (PA) for providing a signal in a baseband, said matched filter network (MFN) comprising: - The first part (SCT1) is located between the output node of the power amplifier (PA) and the first intermediate node (N1). - The second part (SCT2), between the first intermediate node (N1) and the second intermediate node (N2), and - The third part (SCT3) is located between the second intermediate node (N2) and the input node of the antenna (ANT). The three components include an inductor-capacitor LC arrangement configured to have an impedance that matches the output of the power amplifier (PA) in the baseband. The LC arrangements of the first portion (SCT1) and the second portion (SCT2) are further configured to have resonant frequencies suitable for attenuating the harmonic bands of the fundamental frequency band, and respectively include: a series LC arrangement (12) coupled between the first intermediate node (N1) and the ground node (GND), and a series LC arrangement (22) coupled between the second intermediate node (N2) and the ground node (GND). Each series LC arrangement (12, 22) is configured to have an equivalent impedance corresponding to the impedance of a capacitor element (C0) adapted for impedance matching in the fundamental frequency band, and the resonant frequencies (f12, f22) of each series LC arrangement (12, 22) are selected to be distributed in different harmonic bands (HB5, HB4, HB3) of the fundamental frequency band, such that the series LC arrangement (12, 22) whose equivalent impedance corresponds to the impedance of the capacitor element (C0) with the minimum capacitance value has the maximum resonant frequency (f12, f22).

2. The integrated circuit of claim 1, wherein the LC arrangement of the first portion (SCT1) is configured to have a resonant frequency smaller than the resonant frequency of the corresponding LC arrangement of the second portion (SCT2).

3. The integrated circuit according to any one of claims 1 or 2, wherein the first portion (SCT1) further comprises a parallel LC arrangement (11) coupled between the output node of the power amplifier (PA) and the first intermediate node (N1), and The second part (SCT2) further includes a parallel LC arrangement (21) coupled between the first intermediate node (N1) and the second intermediate node (N2).

4. The integrated circuit according to claim 1, wherein the resonant frequency (f11, f21) of each parallel LC arrangement (11, 21) is selected to be distributed in different harmonic bands (HB2) of the fundamental frequency band together with the resonant frequency (f12, f22) of the series LC arrangement (12, 22).

5. The integrated circuit according to any one of claims 3 to 4, wherein the LC arrangement of the first portion (SCT1) and the second portion (SCT2) is configured according to at least one of the following criteria: - The parallel LC arrangement (11) of the first part (SCT1) is configured to have a resonant frequency (f11) in half of the second harmonic frequency band (HB2). - The parallel LC arrangement (21) of the second part (SCT2) is configured to have a resonant frequency (f21) in the other half of the second harmonic frequency band (HB2). - The series LC arrangement (12) of the first part (SCT1) is configured to have a resonant frequency (f12) in the third harmonic band (HB3). - The series LC arrangement (22) of the second part (SCT2) is configured to have a resonant frequency (f22) between the fourth harmonic band (HB4) and the fifth harmonic band (HB5), or in the common part of the fourth harmonic band (HB4) and the fifth harmonic band (HB5).

6. The integrated circuit of claim 1, wherein the third portion (SCT3) comprises an LC arrangement including an inductive element coupled between the second intermediate node (N2) and the input node of the antenna (ANT), and a capacitive element coupled between the input node of the antenna (ANT) and a ground node (GND), the LC arrangement of the third portion (SCT3) being configured to have a minimum quality factor.

7. A method for impedance matching and filtering between the output of a power amplifier (PA) and an antenna (ANT), the power amplifier providing a signal in a baseband, the method comprising dimensioning a virtual matching network (MN0), the virtual matching network (MN0) comprising: -The first section (SCT01) between the output node of the power amplifier (PA) and the first intermediate node (N1). -The second portion (SCT02) between the first intermediate node (N1) and the second intermediate node (N2), and - The third part (SCT03) between the second intermediate node (N2) and the input node of the antenna (ANT). Each of the three parts includes an inductive element and a capacitive element, and the dimensions are formed to have an impedance that matches the output of the power amplifier (PA) in the fundamental frequency band. The method includes forming a real matched filter network (MFN), which involves replacing each inductor element and each capacitor element of the first portion (SCT01) and the second portion (SCT02) of the virtual matching network (MN0) with corresponding inductor-capacitor LC arrangements (11, 12, 21, 22). The LC arrangements are configured to have an equivalent impedance that matches the output of the power amplifier (PA) in the fundamental frequency band and also have resonant frequencies (f11, f12, f21, f22) suitable for attenuating harmonic bands of the fundamental frequency band. The formation of the actual matched filter network (MFN) involves replacing each inductor element with a parallel LC arrangement (11, 21) and each capacitor element with a series LC arrangement (21, 22). For each series LC arrangement, the resonant frequencies (f12, f22) are first selected to be distributed in different harmonic bands (HB5, HB4, HB3) of the fundamental frequency band, and the series LC arrangement (12, 22) that replaces the capacitor element of the virtual matching network (MN0) with the smallest capacitance value has the largest resonant frequency.

8. The method of claim 7, wherein the resonant frequency of the LC arrangement (11, 12) of the first portion (SCT1) of the real matched filter network (MFN) is selected to be lower than the resonant frequency of the corresponding LC arrangement (21, 22) of the second portion (SCT2) of the real matched filter network (MFN).

9. The method according to any one of claims 7 or 8, wherein the first portion (SCT01) of the virtual matching network (MN0) includes an inductive element coupled between the output node of the power amplifier (PA) and the first intermediate node (N1), and a capacitive element coupled between the first intermediate node (N1) and the ground node (GND), and the second portion (SCT02) of the virtual matching network (MN0) includes an inductive element coupled between the first intermediate node (N1) and the second intermediate node (N2), and a capacitive element coupled between the second intermediate node (N2) and the ground node (GND).

10. The method of claim 7, wherein the resonant frequencies (f11, f21) for each parallel LC arrangement (11, 21) are then selected to be distributed together with the resonant frequencies (f12, f22) of the series LC arrangement (12, 22) in different harmonic bands (HB2) of the fundamental frequency band.

11. The method according to any one of claims 9 to 10, wherein the real matched filter network (MFN) is formed according to at least one of the following criteria: - The parallel LC arrangement (11) of the first part (SCT1) has a resonant frequency (fr11) in half of the second harmonic frequency band (HB2). - The parallel LC arrangement (21) of the second part (SCT2) has a resonant frequency (fr21) in the other half of the second harmonic frequency band (HB2). - The series LC arrangement (12) of the first part (SCT1) has a resonant frequency (fr12) in the third harmonic band (HB3). - The series LC arrangement (22) of the second part (SCT2) has a resonant frequency (fr22) between the fourth harmonic band (HB4) and the fifth harmonic band (HB5), or in the common part of the fourth harmonic band (HB4) and the fifth harmonic band (HB5).

12. The method of claim 7, wherein the generation of the real matched filter network (MFN) comprises: The third part (SCT3) of the virtual matching network (MN0) is reproduced. The third part (SCT3) includes an inductive element coupled between the second intermediate node (N2) and the input node of the antenna (ANT), and a capacitive element coupled between the input node (ANT) of the antenna and the ground node (GND). The LC arrangement of the third part (SCT3) is dimensioned to have the minimum quality factor.

13. An integrated circuit, comprising: A power amplifier is configured to provide a signal in the baseband; antenna; and Matched filter networks, including: The first part, coupled between the output node and the first intermediate node of the power amplifier, includes a first inductor-capacitor LC arrangement. This first LC arrangement includes a first series LC arrangement coupled between the first intermediate node and a ground node, and is configured to have an impedance matched to the output of the power amplifier in the fundamental frequency band, and a resonant frequency suitable for attenuating harmonic bands of the fundamental frequency band. The second part, coupled between the first and second intermediate nodes, includes a second LC arrangement comprising a second series LC arrangement coupled between the second intermediate node and a ground node, and is configured to have an impedance matching the output of the power amplifier in the baseband, and a resonant frequency suitable for attenuating the harmonic bands of the baseband. The third part, coupled between the second intermediate node and the input node of the antenna, includes a third LC arrangement configured to have an impedance matched to the output of the power amplifier in the baseband. Each of the first series LC arrangement and the second series LC arrangement is configured to have an equivalent impedance corresponding to the impedance of a capacitor element adapted for impedance matching in the fundamental frequency band, and wherein the associated resonant frequencies of each of the first series LC arrangement and the second series LC arrangement are selected to be distributed in different harmonic bands of the fundamental frequency band, such that the first series LC arrangement and the second series LC arrangement, whose equivalent impedance corresponds to the impedance of the capacitor element having the minimum capacitance value, have the maximum resonant frequency.

14. The integrated circuit of claim 13, wherein the first LC arrangement is further configured to have a resonant frequency lower than that of the second LC arrangement.

15. The integrated circuit according to claim 13, The first LC arrangement further includes: A first parallel LC arrangement is coupled between the output node and the first intermediate node of the power amplifier; and The second LC arrangement further includes a second parallel LC arrangement coupled between the first intermediate node and the second intermediate node.

16. The integrated circuit of claim 15, wherein the associated resonant frequency of each of the first parallel LC arrangement and the second parallel LC arrangement is selected to be distributed in different harmonic bands of the fundamental frequency band together with the associated resonant frequency of each of the first series LC arrangement and the second series LC arrangement.

17. The integrated circuit of claim 15, wherein the first parallel LC arrangement is configured to have a corresponding resonant frequency in one half of the second harmonic band, the second parallel LC arrangement is configured to have a corresponding resonant frequency in the other half of the second harmonic band, the first series LC arrangement is configured to have a corresponding resonant frequency in the third harmonic band, and the second series LC arrangement is configured to have a resonant frequency between the fourth and fifth harmonic bands, or in the common portion of the fourth and fifth harmonic bands.

18. The integrated circuit of claim 13, wherein the third LC arrangement is configured to have a minimum quality factor, the third LC arrangement comprising: An inductive element, coupled between the second intermediate node and the input node of the antenna, and A capacitor element is coupled between the input node and the ground node of the antenna.

19. A method for impedance matching and filtering between the output of a power amplifier and an antenna, the power amplifier being configured to provide a signal in a baseband, the method comprising: A matched filter network is coupled between the power amplifier and the antenna, the matched filter network comprising: In the first part between the output node and the first intermediate node of the power amplifier, The second part between the first intermediate node and the second intermediate node, and The third part between the second intermediate node and the input node of the antenna, The inductor and capacitor in the first inductor-capacitor arrangement are determined to have impedances that match the output of the power amplifier in the fundamental frequency band, and resonant frequencies suitable for attenuating harmonic bands of the fundamental frequency band. The inductor and capacitor in the second inductor-capacitor arrangement are determined to have impedances that match the output of the power amplifier in the fundamental frequency band, and resonant frequencies suitable for attenuating the harmonic bands of the fundamental frequency band; and The inductor and capacitor in the third inductor-capacitor arrangement are determined to have impedances that match the output of the power amplifier located in the fundamental frequency band. The first inductor-capacitor arrangement includes a first series inductor-capacitor arrangement coupled between the first intermediate node and the ground node, and the second inductor-capacitor arrangement includes a second series inductor-capacitor arrangement coupled between the second intermediate node and the ground node. The method further includes: determining that the associated resonant frequencies of each of the first series inductor-capacitor arrangement and the second series inductor-capacitor arrangement are distributed in different harmonic bands of the fundamental frequency band, such that the first series inductor-capacitor arrangement and the second series inductor-capacitor arrangement, whose equivalent impedance corresponds to the impedance of the capacitor element with the minimum capacitance value, have the maximum resonant frequency.

20. The method of claim 19, further comprising: It is determined that the inductor and capacitor of the first inductor-capacitor arrangement have a resonant frequency that is lower than the resonant frequency of the second inductor-capacitor arrangement.

21. The method according to claim 19, The first inductor-capacitor arrangement further includes: A first parallel inductor-capacitor arrangement is coupled between the output node and the first intermediate node of the power amplifier; and The second inductor-capacitor arrangement further includes a second parallel inductor-capacitor arrangement coupled between the first intermediate node and the second intermediate node.

22. The method of claim 21, further comprising: The associated resonant frequencies of each of the first parallel inductor-capacitor arrangement and the second parallel inductor-capacitor arrangement are determined to be distributed together with the associated resonant frequencies of each of the first series inductor-capacitor arrangement and the second series inductor-capacitor arrangement in different harmonic bands of the fundamental frequency band.

23. The method of claim 21, further comprising: The inductor and capacitor in the first parallel inductor-capacitor arrangement are determined to have corresponding resonant frequencies in half of the second harmonic frequency band. Determine that the inductor and capacitor in the second parallel inductor-capacitor arrangement have corresponding resonant frequencies in the other half of the second harmonic frequency band; It is determined that the inductor and capacitor in the first series inductor-capacitor arrangement have corresponding resonant frequencies in the third harmonic frequency band, and The inductor and capacitor in the second series inductor-capacitor arrangement are determined to have a resonant frequency between the fourth harmonic frequency band and the fifth harmonic frequency band, or in the common portion of the fourth harmonic frequency band and the fifth harmonic frequency band.

24. The method of claim 19, wherein the third inductor-capacitor arrangement comprises: An inductive element, coupled between the second intermediate node and the input node of the antenna, and A capacitor element is coupled between the input node and the ground node of the antenna.

25. The method of claim 24, further comprising determining that the inductors and capacitors of the third inductor-capacitor arrangement have a minimum quality factor.

26. A matched filter network coupled between a power amplifier and an antenna, the power amplifier being configured to provide a signal in a baseband, the matched filter network comprising: The first part, coupled between the power amplifier and the output node and the first intermediate node, includes a first inductor-capacitor arrangement configured to have an impedance matching the output of the power amplifier at the baseband, and includes a first series inductor-capacitor arrangement coupled between the first intermediate node and the ground node, and a resonant frequency suitable for attenuating harmonic bands of the baseband. The second part, coupled between the first and second intermediate nodes, includes a second inductor-capacitor arrangement configured to have an impedance matching the output of the power amplifier in the baseband, and includes a second series inductor-capacitor arrangement coupled between the second intermediate node and a ground node, and a resonant frequency suitable for attenuating harmonic bands of the baseband. The third part, coupled between the second intermediate node and the input node of the antenna, includes a third inductor-capacitor arrangement configured to have an impedance matching the output of the power amplifier in the baseband. Each of the first series inductor-capacitor arrangement and the second series inductor-capacitor arrangement is configured to have an equivalent impedance corresponding to the impedance of a capacitor element adapted for impedance matching in the fundamental frequency band, and wherein the associated resonant frequencies of each of the first series inductor-capacitor arrangement and the second series inductor-capacitor arrangement are selected to be distributed in different harmonic bands of the fundamental frequency band, such that the first series inductor-capacitor arrangement and the second series inductor-capacitor arrangement, whose equivalent impedance corresponds to the impedance of the capacitor element having the minimum capacitance value, have the maximum resonant frequency.

27. The matched filter network according to claim 26, The first inductor-capacitor arrangement further includes: A first parallel inductor-capacitor arrangement is coupled between the output node and the first intermediate node of the power amplifier; The second inductor-capacitor arrangement further includes: a second parallel inductor-capacitor arrangement coupled between the first intermediate node and the second intermediate node; and The third inductor-capacitor arrangement is configured to have a minimum quality factor, and the third inductor-capacitor arrangement includes: An inductive element, coupled between the second intermediate node and the input node of the antenna, and A capacitor element is coupled between the input node and the ground node of the antenna.

28. The matched filter network of claim 27, wherein the associated resonant frequency of each of the first parallel inductor-capacitor arrangement and the second parallel inductor-capacitor arrangement is selected to be distributed in different harmonic bands of the fundamental frequency band together with the associated resonant frequency of each of the first series inductor-capacitor arrangement and the second series inductor-capacitor arrangement.

29. The matched filter network of claim 27, wherein the first parallel inductor-capacitor arrangement is configured to have a corresponding resonant frequency in one half of the second harmonic band, the second parallel inductor-capacitor arrangement is configured to have a corresponding resonant frequency in the other half of the second harmonic band, the first series inductor-capacitor arrangement is configured to have a corresponding resonant frequency in the third harmonic band, and the second series inductor-capacitor arrangement is configured to have a resonant frequency between the fourth and fifth harmonic bands, or in the common portion of the fourth and fifth harmonic bands.

Images