WO2019127412A1

WO2019127412A1 - Harmonic control circuit apparatus and method for manufacturing the same

Info

Publication number: WO2019127412A1
Application number: PCT/CN2017/119967
Authority: WO
Inventors: Zhancang WANG; Liangxie YAO
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2017-12-29
Filing date: 2017-12-29
Publication date: 2019-07-04

Abstract

A harmonic control circuit (HCC) apparatus for use in a radio frequency (RF) device as well as a method for manufacturing the HCC apparatus are disclosed. According to an embodiment, the HCC apparatus comprises a planar dielectric substrate, a first conducting layer and a second conducting layer. The first conducting layer is disposed on a first side of the planar dielectric substrate and has a conducting pattern. One or multiple spaced-apart complementary spiral ring resonators are integrated in the conducting pattern. The second conducting layer is disposed on an opposite side of the planar dielectric substrate and faces the first conducting layer. The second conducting layer acts as a ground plane.

Description

HARMONIC CONTROL CIRCUIT APPARATUS AND METHOD FOR MANUFACTURING THE SAME

Technical Field

Embodiments of the disclosure generally relate to the field of electronic components, and, more particularly, to a harmonic control circuit apparatus and a method for manufacturing the same, as well as a radio frequency device, a base station and a terminal device comprising the same.

Background

This section introduces aspects that may facilitate better understanding of the present disclosure. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.

Currently, among various candidates, Doherty power amplifiers (PAs) are mainstream solutions for radio transmitters of infrastructure base stations. Traditional Doherty PA structures use linear amplifier cells such as class-AB/-B and class-C biased carrier and peaking amplifiers. With the development of modern digital pre-distortion (DPD) schemes, it is possible to use nonlinear amplifier cells (e.g., classes -E, -F, and -F ^-1 mode amplifiers) for Doherty PAs to trade off efficiency to linearity.

For both linear and nonlinear amplifiers cells in Doherty PAs, harmonic control could be applied by using harmonic control circuits (HCCs) to increase the overall efficiency. HCCs can, for example, be implemented on a separate printed circuit board (PCB) provided outside an active device package or an active device bare-die. Another way of HCC implementation is on-chip, either by using bond wires to connect capacitors or integrated passive devices (IPDs) , or by monolithically integrating the passive devices on monolithic microwave integrated circuits (MMICs) . The passive devices can be either on the same semiconductor substrate as the active device or on a separate substrate.

Summary

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

One of the objects of the disclosure is to provide an improved harmonic control solution for a radio frequency (RF) device.

According to one aspect of the disclosure, there is provided an HCC apparatus for use in an RF device. The HCC apparatus comprises a planar dielectric substrate, a first conducting layer and a second conducting layer. The first conducting layer is disposed on a first side of the planar dielectric substrate and has a conducting pattern. One or multiple spaced-apart complementary spiral ring resonators are integrated in the conducting pattern. The second conducting layer is disposed on an opposite side of the planar dielectric substrate and faces the first conducting layer. The second conducting layer acts as a ground plane.

In an embodiment of the disclosure, the one or multiple spaced-apart complementary spiral ring resonators are configured to act as an open-circuit termination on at least one desired harmonic frequency.

In an embodiment of the disclosure, the complementary spiral ring resonator takes the form of a hollowed-out slot of a spiral shape, and the conducting pattern takes the form of a microstrip transmission line.

In an embodiment of the disclosure, the spiral shape comprises one of: a circular spiral shape; and a polygonal spiral shape.

In an embodiment of the disclosure, the hollowed-out slot is disposed at the center of the microstrip transmission line.

In an embodiment of the disclosure, the microstrip transmission line has a first region provided with the one or multiple complementary spiral ring resonators and a second region without the one or multiple complementary spiral ring resonators. The first region has a wider width than the second region.

In an embodiment of the disclosure, the second region has a first sub-region with a uniform width and a second sub-region with a tapered width. The second sub-region is disposed between the first region and the first sub-region.

In an embodiment of the disclosure, the spiral shape is determined by parameters including an amount of turns of the spiral shape, a size of the innermost turn, a width between two adjacent turns, and a width of the hollowed-out slot. The parameters are configured to define the desired harmonic frequency and the harmonic suppression level.

In an embodiment of the disclosure, a distance between the multiple complementary spiral ring resonators is configured to define the fundamental frequency.

In an embodiment of the disclosure, the one or multiple spaced-apart complementary spiral ring resonators are configured independent of fundamental frequency matching.

In an embodiment of the disclosure, the one or multiple spaced-apart complementary spiral ring resonators are configured to act as an open-circuit termination over a broadband of harmonic frequencies with deep harmonic suppression levels.

In an embodiment of the disclosure, the RF device comprises an active device, an input matching network, an input bias network, an output matching network and an output bias network. The active device comprises one or more input terminals and one or more output terminals. The input matching network is arranged between the active device and an input node. The input bias network is arranged at the input terminal. The output matching network is arranged between the active device and an output node. The output bias network is arranged at the output terminal.

In an embodiment of the disclosure, the one or multiple spaced-apart complementary spiral ring resonators are inserted into at least one of: a point in the input matching network; a point in the input bias network; a point in the output matching network; a point in the output bias network; a point out of the input matching network and the output matching network; and a point out of the input matching network and the output matching network, while being connected to the input matching network and/or the output matching network.

In an embodiment of the disclosure, the one or multiple spaced-apart complementary spiral ring resonators are configured to be offset a predetermined electrical length from the insertion point to control a reflection phase of the harmonic termination.

In an embodiment of the disclosure, the active device comprises Gallium Nitride (GaN) high electron mobility transistor (HEMT) .

In an embodiment of the disclosure, the planar dielectric substrate is part of: a PCB or a semiconductor chip.

According to another aspect of the disclosure, there is provided an RF device comprising the HCC apparatus according to the above aspect.

In an embodiment of the disclosure, the RF device is one of: a power amplifier; a radio unit (RU) of a base station; and an RU of a terminal device.

According to another aspect of the disclosure, there is provided a base station. The base station comprises a processor, a memory, a power amplifier and an antenna unit. The memory contains instructions executable by the processor to implement functions of the base station. The power amplifier is configured to amplify an RF signal and comprises the HCC apparatus according to the above aspect. The antenna unit is configured to transmit the amplified RF signal.

According to another aspect of the disclosure, there is provided a terminal device. The terminal device comprises a processor, a memory, a power amplifier and an antenna unit. The memory contains instructions executable by the processor to implement functions of the terminal device. The power amplifier is configured to amplify an RF signal and comprises the HCC apparatus according to the above aspect. The antenna unit is configured to transmit the amplified RF signal.

According to another aspect of the disclosure, there is provided a method for manufacturing an HCC apparatus. The method comprises providing a planar dielectric substrate. The method further comprises forming a first conducting layer on a first side of the planar dielectric substrate such that the first conducting layer has a conducting pattern. One or multiple spaced-apart complementary spiral ring resonators are integrated in the conducting pattern. The method further comprises forming, on an opposite side of the planar dielectric substrate, a second conducting layer that faces the first conducting layer and acts as a ground plane.

In an embodiment of the disclosure, the complementary spiral ring resonator is formed as a hollowed-out slot of a spiral shape, and the conducting pattern is formed as a microstrip transmission line.

According to some embodiment (s) of the disclosure, at least one of harmonic suppression bandwidth, fundamental frequency band matching, arrangement flexibility and size/cost can be improved.

Brief Description of the Drawings

These and other objects, features and advantages of the disclosure will become apparent from the following detailed description of illustrative embodiments thereof, which are to be read in connection with the accompanying drawings.

FIG. 1 shows the efficiencies of different Doherty PAs with and without harmonic control;

FIGs. 2A-2B are diagrams each showing an existing HCC apparatus;

FIGs. 3A-3B are structural views showing an HCC apparatus according to an embodiment of the disclosure;

FIGs. 4A-4B are plan views each showing an HCC apparatus according to another embodiment of the disclosure;

FIGs. 5A-5B show a simulated example for the HCC apparatus of FIG. 4B;

FIG. 6 shows S-parameter curves of the simulated example;

FIG. 7 is an input impedance plot of the simulated example on rectangular chart;

FIG. 8 is an input impedance plot of the simulated example on Smith chart;

FIG. 9 shows the possible arrangements of an HCC apparatus according to an embodiment in an RF device;

FIGs. 10A-10B show different application scenarios of an HCC apparatus according to an embodiment of the disclosure;

FIG. 11 is a block diagram showing an RF device according to an embodiment of the disclosure;

FIG. 12 is a block diagram showing a base station according to an embodiment of the disclosure;

FIG. 13 is a block diagram showing a terminal device according to an embodiment of the disclosure; and

FIG. 14 is a flowchart illustrating a method for manufacturing an HCC apparatus according to an embodiment of the disclosure.

Detailed Description

For the purpose of explanation, details are set forth in the following description in order to provide a thorough understanding of the embodiments disclosed. It is apparent, however, to those skilled in the art that the embodiments may be implemented without these specific details or with an equivalent arrangement.

FIG. 1 shows the influence of harmonic control on the efficiencies of Doherty PAs in an ideal case with different carrier and peaking amplifier topologies. The dashed curves in FIG. 1 correspond to Doherty PAs without harmonic control, while the solid curves correspond to Doherty PAs with harmonic control. It can be seen that the harmonic control can significantly increase the efficiencies of Doherty PAs in the ideal case. In particular, a harmonically controlled Doherty PA with nonlinear amplifier cells can obtain 100%ideal efficiency points at the breakpoint (corresponding to -6 dB back-off) and peak power point (corresponding to 0 dB back-off) , respectively. Therefore, there exists a need to improve the performance of harmonic control.

In the designs for next generation RF PAs, broadband or multiband RF PAs have been developed by using, for example, Gallium Nitride (GaN) high electron mobility transistor (HEMT) technology. Since PAs with GaN HEMTs are of Class-E, an HCC with a broader harmonic tuning bandwidth is highly desired due to the broad fundamental frequency band. For example, if a PA design is targeting to cover a 100 MHz wide fundamental bandwidth, the second harmonic bandwidth requirement would be 200 MHz wide. This poses a severe challenge to HCC design.

In the existing solutions shown in FIGs. 2A-2B, the HCC 221 comprises a complementary open-loop resonator (e.g., complementary split ring resonator simply referred to as CSRR) 224/324 that is integrated in a conducting pattern 222, to produce a shunt resonator configured to act as a short-circuit termination on at least one tuned frequency. The split ring 224 has a “C” shape and the gaps are separated by 180 degrees in arrangement. The split ring 324 has a shape with multiple fingers. The conducting pattern 222 is provided in a first conducting layer. The first conducting layer is disposed on a first side of a planar dielectric substrate 223 and faces a second conducting layer on the opposite side of the planar dielectric substrate 223. The second conducting layer acts as a ground plane.

For the above existing HCC solutions, there is still some room for improvement in the aspects of harmonic suppression bandwidth, fundamental frequency band matching, arrangement flexibility and cost/size.

The present disclosure proposes an improved HCC solution. Hereinafter, the solution will be described in detail with reference to FIGs. 3-14.

FIGs. 3A-3B are structural views showing an HCC apparatus according to an embodiment of the disclosure. FIG. 3A is a plan view and FIG. 3B is a sectional view taken along the line A-A’ in FIG. 3A. As shown, the HCC apparatus 30 comprises a planar dielectric substrate 32, a first conducting (e.g., metallic) layer 34 and a second conducting (e.g., metallic) layer 36. The first conducting layer 34 is disposed on a first side (e.g., the upper side in FIG. 3B) of the planar dielectric substrate 32 and has a conducting pattern 342. The second conducting layer 36 is disposed on an opposite side (e.g., the lower side in FIG. 3B) of the planar dielectric substrate 32 and faces the first conducting layer 34. The second conducting layer 36 is configured to act as a ground plane. Note that the opposite side refers to the side opposite to the first side of the planar dielectric substrate.

Since a planar structure is used, the HCC apparatus 30 can have a compact size and a simple fabrication process, and can be compatible with a wide range of substrate based technologies. For example, the HCC apparatus 30 can be realized in either an integrated circuit or a printed circuit board (PCB) .

The conducting pattern 342 may take the form of a microstrip transmission line. There is a complementary spiral ring resonator 344 integrated in the conducting pattern 342. The complementary spiral ring resonator 344 may take the form of a hollowed-out slot of a spiral shape, for example, the circular spiral shape in FIG. 3A. In other words, by replacing some parts of a conductive planar structure with apertures (for example, through etching) , the original conductive planar structure is changed into two counterparts (the slot 344 and the conducting pattern 342) complementary to each other.

When an RF signal passes through the microstrip transmission line 342, a time-varying electric field parallel to the spiral ring axis is formed. To ensure the hollowed-out slot 344 to be sufficiently excited by the electric field applied parallel to the spiral ring axis, the hollowed-out slot 344 may be optionally disposed at the center of the microstrip transmission line 342.

For example, the spiral shape may be determined by four parameters. The first parameter is the amount (or number) of turns of the spiral shape, which may be denoted as N herein. In the example of FIG. 3A, N equals to 2. Note that N is not limited to an integer and may equal to any other suitable value such as 0.8, 2.5, or the like. That is, part of one turn or multiple turns plus part of one turn is also possible. The second parameter is the size of the innermost turn, which may be represented by the radius of the innermost turn in the case of the circular spiral shape. It may also be called as inner radius (RI) herein.

The third parameter is the width between two adjacent turns, which may also be referred to as strip width (W) herein. The fourth parameter is the width of the hollowed-out slot, which may also be referred to as slot spacing (S) herein. Although W and S are shown to have a fixed value, each of them may also have a varying value along the extending direction of the slot. The above four parameters may be configured to define the desired harmonic frequency and the harmonic suppression level.

FIGs. 4A-4B are plan views each showing an HCC apparatus according to another embodiment of the disclosure. In the embodiment of FIG. 4A, four spaced-apart complementary spiral ring resonators 344 shown in FIG. 3A are integrated in the microstrip transmission line 342. That is, a sequence of multiple identical resonator cells may be employed. The distance (or spacing) between the multiple resonator cells may be configured to define the fundamental frequency. Since the harmonic frequency may be defined by the above four parameters, the configuration of the harmonic frequency can be decoupled from the configuration of the fundamental frequency. As a result, the HCC apparatus can be made more compact such that it can be deployed into a 50 Ohm trace. The arrangement position of the HCC apparatus can also be more flexible.

The microstrip transmission line 342 has a first region 3421 provided with the multiple resonator cells and a second region 3422 without any resonator cells. The first region 3421 may have a wider width than the second region 3422. Optionally, the second region 3422 may have a first sub-region 3423 with a uniform width (e.g., a 50 Ohm trace) and a second sub-region 3424 with a tapered width. The tapered sub-region 3424 may be disposed between the first region 3421 and the first sub-region 3423 to compensate the discontinuity therebetween.

The embodiment of FIG. 4B is basically the same as that of FIG. 4A except that each resonator cell has a rectangular spiral shape instead of the circular spiral shape. It should be noted that the present disclosure is not limited to these examples. Optionally, in addition to the circular and rectangular spiral shapes, the hollowed-out slot may take any other polygonal spiral shape (e.g., triangle, quadrilateral, square, pentagon, hexagon, octagon, and so on) , any other suitable regular or irregular spiral shape.

The HCC apparatus 30 described above can be configured to act as an open-circuit termination on at least one desired harmonic frequency. When it is used, an RF signal may be input via a first electrical length of wire extending from the first end (e.g., the left end in FIGs. 3A and 4A-4B) of the transmission line 342, and may be output via a second electrical length extending from the second end (e.g., the right end in FIGs. 3A and 4A-4B) of the transmission line 342.

FIGs. 5A-5B show a simulated example for the HCC apparatus of FIG. 4B. FIG. 5A is a schematic plan view showing one resonator cell. Similar to the example of FIG. 3A, the spiral shape may be determined by four parameters, i.e. the number of turns N, the strip width W, the slot spacing S and the size of the innermost turn. For the rectangular spiral shape, the size of the innermost turn may be presented by three lengths, i.e. the first inside segment length L1, the second inside segment length L2, and the third inside segment length L3.

FIG. 5B shows the electromagnetic (EM) simulation setup for verifying the S-parameter performance of the HCC apparatus. In this simulation, the fundamental frequency was selected as 2.3 GHz. This resulted in a second harmonic tuning frequency around 4.6 GHz. A PCB with the model number “Rogers RO4350B 20mil” was used. The parameters of one resonator cell were selected as: L1 = 2mm, L2 =0.6mm, L3 = 2.2mm, W = 0.2mm, S = 0.2mm and N = 2. The physical length of the spiral ring slots was chosen to correspond to a proper electrical length to be open-circuited at the second harmonic range. The characteristic impedance of the transmission line was set as 50 Ohm with a taper to compensate the discontinuity to the width of the microstrip trace holding the spiral ring slots so that it could be deployed at the 50 Ohm microstrip trace.

FIG. 6 shows S-parameter curves of the simulated example. The dashed curve S ₁₁ represents the simulated reflection (i.e. return loss simply referred to as RL) in dB-scale of HCC input port versus frequency. The solid curve S ₂₁ represents the simulated transmission (i.e. insertion loss simply referred to as IL) in dB-scale between HCC input port and output port versus frequency. As mentioned above, the fundamental frequency f ₀ was chosen to be 2.3 GHz band. At f ₀ the return loss S ₁₁ is very low (< -50 dB) . This means an almost perfect match to the port impedance Z ₀ over a broad frequency range.

However, at the second harmonic frequency (i.e. 2*f ₀) range, the insertion loss S ₂₁ is very low, while the return loss S ₁₁ is very high. This means that the HCC apparatus presents almost total reflection (approaching 0 dB RL) to the HCC input port and consequently nearly perfect suppression (more than 45 dB IL in the worst case) over a broadband frequency range of 4.55～4.68 GHz. For frequencies approximating 2*f ₀, the HCC apparatus presents high impedance approximating an open-circuit termination.

For suppression level of 10 dB, the HCC apparatus can provide a normalized suppression bandwidth of 21.8%, wherein a normalized suppression bandwidth can be defined as the ratio between the frequency range and the center frequency. Therefore, by using the HCC apparatus of the present disclosure, the suppression bandwidth for the second harmonic can be greatly increased to meet the broadband harmonic termination requirements. In addition, broadband fundamental matching can be observed from FIG. 6. This greatly reduces the difficulty of fundamental matching impact when terminating the second harmonic for high efficiency power amplification.

FIG. 7 is an input impedance plot of the simulated example on rectangular chart. As shown, around the fundamental frequency (2.3 GHz) , the input impedance is about 50 Ohm, which means an almost perfect impedance matching. Meanwhile, around the second harmonic frequency (4.6 GHz) , the input impedance is very high, which means a nearly perfect suppression.

FIG. 8 is an input impedance plot of the simulated example on Smith chart. As shown, the simulated input impedance trace is presented in polar form on Smith chart. When the frequency changes around the fundamental frequency (2.3 GHz) , the input impedance always changes along a trace surrounding Z ₀ (50 Ohm) . Correspondingly, when the frequency changes around the second harmonic frequency (4.6 GHz) , the input impedance always changes along a trace at the edge of the chart, which represents an open-circuit termination over frequencies.

Thus, the fundamental frequency matching is completely independent of the harmonic phase rotations, since the fundamental matching is cycling only a quite limited area around the target load impedance (e.g., 50 Ohm) . This behavior is like that of a clock. The pivot does not change the position away from the center of a clock while the minute hand rotates clockwise to point the round clock edge with an arbitrary phase shift.

As mentioned above, when the HCC apparatus 30 is used, an RF signal may be input via a first electrical length of wire extending from the first end of the transmission line 342. This first electrical length of wire may be used as an offset line. When the length of the offset line is increased, the harmonic impedance rotates clockwise around the fundamental matching impedance as the center. Thus, the length of the offset line can be adjusted to control a reflection phase of the harmonic termination. By doing this, it can act as an arbitrary open-circuit termination at all harmonic bands by adding a specific length of offset line before the HCC apparatus in series, without impacting the fundamental frequency matching.

It should be noted that the present disclosure is not limited to the above examples. Optionally, it is also possible that the multiple spaced-apart resonator cells are not identical to each other at the cost of increased complexity in designing and manufacturing process. For example, some resonator cell (s) may have a phase shift relative to other resonator cell (s) along the extending direction of the spiral shape.

FIG. 9 shows the possible arrangements of an HCC apparatus according to an embodiment in an RF device. The RF device 900 comprises an active device 902 with an input terminal 9021 for receiving an RF input signal and an output terminal 9022. Although a single input terminal and a single output terminal are shown, the active device 902 may also include additional input and output terminals. A bias network 904 is connected at the output terminal 9022. The output terminal 9022 is also connected to a matching network 906 which can provide an output RF signal.

As mentioned above, for the HCC apparatus 30 described above, the fundamental matching can be independent from the harmonic tuning process. Thus, the HCC apparatus can be flexibly inserted into at least one of: the position-1 inside the bias network 904, the position-2 inside the matching network 906, and the position-3 out of the matching network while being connected to the matching network 906. The HCC apparatus may be configured to receive the output signal generated by the active device 902 and further configured to control at least two harmonics of the operation frequency band of the active device 902, by providing harmonic terminations on adjacent two tuned frequencies.

FIGs. 10A-10B show different application scenarios of an HCC apparatus according to an embodiment of the disclosure. As shown, the HCC apparatus is applied in an RF device 100 such as an RF power amplifier for efficiency enhancement. The RF device 100 comprises an active device 102 such as a GaN HEMT power transistor. The active device 102 comprises an input terminal A, an output terminal B, an input matching network 104 arranged between the active device 102 and an input node C, an input bias network 106 arranged at the input terminal A, an output matching network 108 arranged between the active device 102 and an output node D, and an output bias network 110 arranged at the output terminal B.

The HCC apparatus may be configured to receive either the input or output signal generated by the active device 102 and further configured to control at least two harmonics of the operation frequency band of the active device 102, by providing harmonic terminations on adjacent two tuned frequencies.

In FIG. 10A, the HCC apparatus is placed after the output matching network 108 on the signal path. Thus, it can provide a total “fundamental matching free” HCC over a broad bandwidth. In FIG. 10B, the HCC apparatus is placed after the combination of “quarter wave line plus RF bypass capacitors” on the bias path. This branch placement enables the HCC apparatus to be easily decoupled from the matching network 108.

However, the present disclosure is not limited to the above examples. Optionally, the HCC apparatus may be inserted into at least one of the following points for input and/or output harmonic termination purpose:

a point in the input matching network 104;

a point in the input bias network 106;

a point in the output matching network 108;

a point in the output bias network 110 (e.g., inserted into the quarter wave transmission line in FIG. 10B) ;

a point out of the input matching network 104 and the output matching network 108; and

a point out of the input matching network 104 and the output matching network 108, while being connected to the input matching network 104 and/or the output matching network 108.

Thus, it can provide high flexibility of integration of harmonic termination within matching networks, signal lines or bias lines.

Further, optionally, the active device may comprise more than one input and/or output terminals. This case may relate to, for example, Doherty, envelope tracking, dynamic load modulation, and so on.

FIG. 11 is a block diagram showing an RF device according to an embodiment of the disclosure. As shown, the RF device 1100 includes the HCC apparatus 30 described above. As an example, the RF device 1100 may be a power amplifier such as a Doherty PA. As another example, the RF device 1100 may be a radio unit (e.g., remote radio unit simply referred to as RRU) of a base station. As another example, the radio device 1300 may be an RU of a terminal device such as a mobile phone. The other configurations of the PA and the RU of the base station or the mobile phone may be well known to those skilled in the art, and thus the detailed description thereof is omitted here.

FIG. 12 is a block diagram showing a base station (BS) according to an embodiment of the disclosure. As shown, the BS 1200 (e.g., an evolved Node B simply referred to as eNB) comprises a processor 1202, a memory 1204, a PA 1206 and an antenna unit 1208. The memory 1204 contains instructions executable by the processor 1202 to implement various functions of the BS 1200. The BS 1200 may support any suitable generation communication protocols, including, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the future fifth generation (5G) communication protocols, and/or any other protocols either currently known or to be developed in the future. The PA 1206 includes the HCC apparatus 30 described above and is configured to amplify an RF signal. The antenna unit 1208 is configured to transmit the amplified RF signal.

The PA 1206 may be a component of a transceiver configured to communicate with the antenna unit 1208, and to provide signals to and receive signals from the processor 1202. These signals sent and received by the processor 1202 may comprise signaling information in accordance with an air interface standard of an applicable cellular system. In addition, these signals may comprise speech data, user requested data, and/or the like.

FIG. 13 is a block diagram showing a terminal device according to an embodiment of the disclosure. The term “terminal device” refers to any end device that can access a wireless communication network and receive services therefrom. By way of example and not limitation, the terminal device refers to a mobile terminal, user equipment (UE) , or other suitable device. The UE may be, for example, a Subscriber Station (SS) , a Portable Subscriber Station, a Mobile Station (MS) , or an Access Terminal (AT) . The terminal device may include, but not limited to, portable computers, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, a mobile phone, a cellular phone, a smart phone, a tablet, a wearable device, a personal digital assistant (PDA) , a vehicle, and the like.

As shown, the terminal device 1300 comprises a processor 1302, a memory 1304, a PA 1306 and an antenna unit 1308. The memory 1304 contains instructions executable by the processor 1302 to implement various functions of the terminal device 1300. The PA 1306 includes the HCC apparatus 30 described above and is configured to amplify an RF signal. The antenna unit 1308 is configured to transmit the amplified RF signal.

The PA 1306 may be a component of a transceiver configured to communicate with the antenna unit 1308, and to provide signals to and receive signals from the processor 1302. These signals sent and received by the processor 1302 may comprise signaling information in accordance with an air interface standard of an applicable cellular system, and/or any number of different wired or wireless networking techniques, comprising but not limited to wireless-fidelity (Wi-Fi) , wireless local access network (WLAN) techniques such as institute of electrical and electronics engineers (IEEE) 802.11, 802.16 and/or the like. In addition, these signals may comprise speech data, user generated data, user requested data, and/or the like. In this regard, the terminal device may be capable of operating with one or more air interface standards, communication protocols, modulation types, access types, and/or the like.

The terminal device 1300 may also comprise a user interface comprising, for example, an earphone or speaker, a ringer, a microphone, a display, a user input interface, and/or the like, which may be operationally coupled to the processor 1302. In this regard, the processor 1302 may comprise user interface circuitry configured to control at least some functions of one or more elements of the user interface, such as, the speaker, the ringer, the microphone, the display, and/or the like. The processor 1302 and/or user interface circuitry may be configured to control one or more functions of one or more elements of the user interface through computer program instructions (e.g., software and/or firmware) stored on the memory 1304.

FIG. 14 is a flowchart illustrating a method for manufacturing an HCC apparatus according to an embodiment of the disclosure. At block 1402, a planar dielectric substrate is provided. For example, the planar dielectric substrate may be part of a PCB or a semiconductor chip.

At block 1404, a first conducting layer is formed on a first side of the planar dielectric substrate such that the first conducting layer has a conducting pattern in which one or multiple spaced-apart complementary spiral ring resonators are integrated. For example, a conducting film may be formed on the first side of the planar dielectric substrate. Then, a patterning process may be performed on the conducting film to form the conducting pattern.

At block 1406, a second conducting layer is formed on an opposite side of the planar dielectric substrate. The second conducting layer faces the first conducting layer and acts as a ground plane. It should be noted that two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved.

In general, the various exemplary embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the disclosure is not limited thereto. While various aspects of the exemplary embodiments of this disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

As such, it should be appreciated that at least some aspects of the exemplary embodiments of the disclosure may be practiced in various components such as integrated circuit chips and modules. It should thus be appreciated that the exemplary embodiments of this disclosure may be realized in an apparatus that is embodied as an integrated circuit, where the integrated circuit may comprise circuitry (as well as possibly firmware) for embodying at least one or more of a data processor, a digital signal processor, baseband circuitry and radio frequency circuitry that are configurable so as to operate in accordance with the exemplary embodiments of this disclosure.

It should be appreciated that at least some aspects of the exemplary embodiments of the disclosure may be embodied in computer-executable instructions, such as in one or more program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types when executed by a processor in a computer or other device. The computer executable instructions may be stored on a computer readable medium such as a hard disk, optical disk, removable storage media, solid state memory, RAM, etc. As will be appreciated by one of skill in the art, the function of the program modules may be combined or distributed as desired in various embodiments. In addition, the function may be embodied in whole or in part in firmware or hardware equivalents such as integrated circuits, field programmable gate arrays (FPGA) , and the like.

References in the present disclosure to “one embodiment” , “an embodiment” and so on, indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to implement such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It should be understood that, although the terms “first” , “second” and so on may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of the disclosure. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed terms.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present disclosure. As used herein, the singular forms “a” , “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” , when used herein, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof. The terms “connect” , “connects” , “connecting” and/or “connected” used herein cover the direct and/or indirect connection between two elements.

The present disclosure includes any novel feature or combination of features disclosed herein either explicitly or any generalization thereof. Various modifications and adaptations to the foregoing exemplary embodiments of this disclosure may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings. However, any and all modifications will still fall within the scope of the non-Limiting and exemplary embodiments of this disclosure.

Claims

A harmonic control circuit (HCC) apparatus (30) for use in a radio frequency (RF) device (1100) , the HCC apparatus (30) comprising:

a planar dielectric substrate (32) ;

a first conducting layer (34) that is disposed on a first side of the planar dielectric substrate (32) and has a conducting pattern (342) , wherein one or multiple spaced-apart complementary spiral ring resonators (344) are integrated in the conducting pattern (342) ; and

a second conducting layer (36) that is disposed on an opposite side of the planar dielectric substrate (32) and faces the first conducting layer (34) , the second conducting layer (36) acting as a ground plane.
The HCC apparatus (30) according to claim 1, wherein the one or multiple spaced-apart complementary spiral ring resonators (344) are configured to act as an open-circuit termination on at least one desired harmonic frequency.
The HCC apparatus (30) according to claim 1 or 2, wherein the complementary spiral ring resonator (344) takes the form of a hollowed-out slot of a spiral shape, and the conducting pattern (342) takes the form of a microstrip transmission line.
The HCC apparatus (30) according to claim 3, wherein the spiral shape comprises one of:

a circular spiral shape; and a polygonal spiral shape.
The HCC apparatus (30) according to claim 3 or 4, wherein the hollowed-out slot is disposed at the center of the microstrip transmission line.
The HCC apparatus (30) according to any of claims 3 to 5, wherein the microstrip transmission line has a first region (3421) provided with the one or multiple complementary spiral ring resonators (344) and a second region (3422) without the one or multiple complementary spiral ring resonators (344) , the first region (3421) having a wider width than the second region (3422) .
The HCC apparatus (30) according to claim 6, wherein the second region (3422) has a first sub-region (3423) with a uniform width and a second sub-region (3424) with a tapered width, the second sub-region (3424) being disposed between the first region (3421) and the first sub-region (3423) .
The HCC apparatus (30) according to any of claims 3 to 7, wherein the spiral shape is determined by parameters including an amount of turns of the spiral shape, a size of the innermost turn, a width between two adjacent turns, and a width of the hollowed-out slot; and

wherein the parameters are configured to define the desired harmonic frequency and the harmonic suppression level.
The HCC apparatus (30) according to any of claims 3 to 8, wherein a distance between the multiple complementary spiral ring resonators (344) is configured to define the fundamental frequency.
The HCC apparatus (30) according to any of claims 1 to 9, wherein the one or multiple spaced-apart complementary spiral ring resonators (344) are configured independent of fundamental frequency matching.
The HCC apparatus (30) according to any of claims 1 to 10, wherein the one or multiple spaced-apart complementary spiral ring resonators (344) are configured to act as an open-circuit termination over a broadband of harmonic frequencies with deep harmonic suppression levels.
The HCC apparatus (30) according to any of claims 1 to 11, wherein the RF device (100) comprises:

an active device (102) comprising one or more input terminals and one or more output terminals;

an input matching network (104) arranged between the active device (102) and an input node;

an input bias network (106) arranged at the input terminal;

an output matching network (108) arranged between the active device (102) and an output node; and

an output bias network (110) arranged at the output terminal.
The HCC apparatus (30) according to claim 12, wherein the one or multiple spaced-apart complementary spiral ring resonators (344) are inserted into at least one of:

a point in the input matching network (104) ;

a point in the input bias network (106) ;

a point in the output matching network (108) ;

a point in the output bias network (110) ;

a point out of the input matching network (104) and the output matching network (108) ; and

a point out of the input matching network (104) and the output matching network (108) , while being connected to the input matching network (104) and/or the output matching network (108) .
The HCC apparatus (30) according to claim 13, wherein the one or multiple spaced-apart complementary spiral ring resonators (344) are configured to be offset a predetermined electrical length from the insertion point to control a reflection phase of the harmonic termination.
The HCC apparatus (30) according to any of claims 12 to 14, wherein the active device (102) comprises Gallium Nitride (GaN) high electron mobility transistor (HEMT) .
The HCC apparatus (30) according to any of claims 1 to 15, wherein the planar dielectric substrate (32) is part of:

a printed circuit board (PCB) or a semiconductor chip.
A radio frequency (RF) device (1100) comprising the HCC apparatus (30) according to any of claims 1 to 16.
The RF device (1100) according to claim 17, wherein the RF device (1100) is one of:

a power amplifier; a radio unit (RU) of a base station; and an RU of a terminal device.
A base station (1200) comprising:

a processor (1202) ;

a memory (1204) , the memory (1204) containing instructions executable by the processor (1202) to implement functions of the base station (1200) ;

a power amplifier (1206) configured to amplify a radio frequency (RF) signal and comprising the HCC apparatus (30) according to any of claims 1 to 16; and

an antenna unit (1208) configured to transmit the amplified RF signal.
A terminal device (1300) comprising:

a processor (1302) ;

a memory (1304) , the memory (1304) containing instructions executable by the processor (1302) to implement functions of the terminal device (1300) ;

a power amplifier (1306) configured to amplify a radio frequency (RF) signal and comprising the HCC apparatus (30) according to any of claims 1 to 16; and

an antenna unit (1308) configured to transmit the amplified RF signal.
A method for manufacturing a harmonic control circuit (HCC) apparatus (30) , the method comprising:

providing (1402) a planar dielectric substrate (32) ;

forming (1404) a first conducting layer (34) on a first side of the planar dielectric substrate (32) such that the first conducting layer (34) has a conducting pattern (342) , wherein one or multiple spaced-apart complementary spiral ring resonators (344) are integrated in the conducting pattern (342) ; and

forming (1406) , on an opposite side of the planar dielectric substrate (32) , a second conducting layer (36) that faces the first conducting layer (34) and acts as a ground plane.
The method according to claim 21, wherein the complementary spiral ring resonator (344) is formed as a hollowed-out slot of a spiral shape, and the conducting pattern (342) is formed as a microstrip transmission line.