CASCADE HIGH-FREQUENCY DEVICES AND METHODS FOR THEIR OPERATION AND MANUFACTURING

Abstract

A cascaded radio frequency (RF) device comprises a first RF chip containing a first local oscillator designed to generate and output a first local oscillator signal during an operating time interval, a second RF chip containing a second local oscillator designed to generate and output a second local oscillator signal during the operating time interval, and a power combiner designed to combine the first local oscillator signal and the second local oscillator signal into a combined local oscillator signal and output the combined local oscillator signal to an input of the first RF chip and to an input of the second RF chip, wherein the first local oscillator signal and the second local oscillator signal exhibit the same frequency response during the operating time interval.

Description

TECHNICAL AREA

[0001] The present disclosure relates to cascaded radio frequency (RF) devices and methods for operating and manufacturing cascaded RF devices. BACKGROUND

[0002] To increase the angular resolution of radar sensors, the number of transmit and receive channels can be increased to achieve a larger aperture. A higher number of channels can be realized by cascading multiple radar MMICs (monolithic integrated microwave circuits), where a primary MMIC can supply the other secondary MMICs and itself with a common local oscillator signal. A guaranteed minimum output power of the primary local oscillator signal and a required minimum input power at the secondary MMICs can limit the maximum number of MMICs and the maximum possible spacing between them on a printed circuit board (PCB). Additionally, for cost reasons, often only inexpensive PCB laminates can be used, which typically result in higher attenuation of the local oscillator signals.The use of inexpensive PCB laminates may therefore be limited, as the required length of the local oscillator signal often cannot be achieved.

[0003] Manufacturers and developers of RF devices are constantly striving to improve their products. In this context, it may be desirable to provide cascaded RF devices with improved performance at a lower cost, thus at least partially resolving the problems identified above. Additionally, it may be desirable to provide suitable procedures for the operation and manufacture of such cascaded RF devices. SUMMARY

[0004] One aspect of the present disclosure relates to a cascaded radio frequency (RF) device. The cascaded RF device comprises a first RF chip including a first local oscillator designed to generate and output a first local oscillator signal during an operating time interval. The cascaded RF device further comprises a second RF chip including a second local oscillator designed to generate and output a second local oscillator signal during the operating time interval. The cascaded RF device further comprises a power combiner designed to combine the first local oscillator signal and the second local oscillator signal into a combined local oscillator signal and to output the combined local oscillator signal to an input of the first RF chip and to an input of the second RF chip.The first local oscillator signal and the second local oscillator signal have the same frequency response during the operating time interval.

[0005] Another aspect of the present disclosure relates to a method for operating a cascaded RF device. The method comprises the process of generating and outputting a first local oscillator signal by a first local oscillator of a first RF chip during an operating time interval. The method further comprises generating and outputting a second local oscillator signal by a second local oscillator of a second RF chip during the operating time interval. The method further comprises the process of combining the first local oscillator signal and the second local oscillator signal into a combined local oscillator signal by a power combiner. The method further comprises the process of outputting the combined local oscillator signal by the power combiner to an input of the first RF chip and to an input of the second RF chip.The first local oscillator signal and the second local oscillator signal have the same frequency response during the operating time interval.

[0006] Another aspect of the present disclosure relates to a method for manufacturing a cascaded RF device. The method comprises an arrangement of a first RF chip including a first local oscillator configured to generate and output a first local oscillator signal during an operating time interval. The method further comprises an arrangement of a second RF chip including a second local oscillator configured to generate and output a second local oscillator signal during the operating time interval. The method further comprises an arrangement of a power combiner configured to combine the first local oscillator signal and the second local oscillator signal into a combined local oscillator signal and to output the combined local oscillator signal to an input of the first RF chip and to an input of the second RF chip.The first local oscillator signal and the second local oscillator signal have the same frequency response during the operating time interval.

[0007] The person skilled in the art will recognize additional features and advantages when reading the following detailed description and examining the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present disclosure is illustrated by way of example, and not as a limitation, by the figures in the accompanying drawings, in which the same reference numerals refer to similar or identical elements. The elements in the drawings are not necessarily to scale with one another. The features of the various illustrated examples may be combined, provided they are not mutually exclusive. Fig. Figure 1 schematically illustrates a cascaded RF device 100 according to the revelation. Fig. Figure 2 schematically illustrates a cascaded RF device 200. Fig. Figure 3 illustrates a flowchart of a method for operating a cascaded RF device according to the disclosure. Fig. Figure 4 illustrates a flowchart of a process for manufacturing a cascaded RF device according to the disclosure. DETAILED DESCRIPTION

[0009] The following detailed description refers to the accompanying drawings, which illustrate certain aspects under which the disclosure can be put into practice. Other aspects may be used, and structural or logical modifications may be made, without departing from the concept of the present disclosure. Therefore, the following detailed description is not to be understood in a restrictive sense, and the concept of the present disclosure is defined by the accompanying claims.

[0010] Referring to the Fig. Figure 1 is a schematic illustration of a cascaded radio frequency device (RF device) (or system) 100 according to the disclosure. The RF device 100 can include a first RF chip 2A with a first local oscillator 4A. The first local oscillator 4A can be configured to generate and output a first local oscillator signal 6A during an operating time interval. The RF device 100 can further include a second RF chip 2B with a second local oscillator 4B. The second local oscillator 4B can be configured to generate and output a second local oscillator signal 6B during the operating time interval. The first local oscillator signal 6A and the second local oscillator signal 6B can have the same frequency response during the operating time interval.The RF device 100 can further include a power combiner 8, which is designed to combine the first local oscillator signal 6A and the second local oscillator signal 6B into a combined local oscillator signal 10 and to output the combined local oscillator signal 10 to an input 12A of the first RF chip 2A and to an input 12B of the second RF chip 2B. The RF device 100 can optionally include a power divider 20, the function of which will be discussed later.

[0011] The following describes the features of the first RF chip 2A. It should be noted that the second RF chip 2B may incorporate some or all of the features of the first RF chip 2A. In some examples, the first RF chip 2A and the second RF chip 2B may have the same design and / or specifications. It is understood that the RF device 100 may contain 100 additional RF chips, the number of which may depend on the specific design of the RF device 100. The first RF chip 2A may be made of or contain any semiconductor material, such as silicon. The first RF chip 2A (or its electronic circuitry) may be designed to operate in a frequency range greater than approximately 1 GHz, and in some examples, greater than approximately 10 GHz. Accordingly, the first RF chip 2A may also be referred to as an RF (Radio Frequency) chip, high-frequency chip, or microwave frequency chip.In particular, the first RF chip 2A can be designed to operate in an RF or microwave frequency range extending from approximately 1 GHz to approximately 1 THz, especially from approximately 10 GHz to approximately 300 GHz. Microwave circuits can include, for example, microwave transmitters, microwave receivers, microwave transceivers, microwave sensors, microwave detectors, or the like. RF devices according to the disclosure can be used for radar applications where the frequency of the RF signals can be modulated. The first RF chip 2A can therefore also be referred to as a radar chip. In particular, the first RF chip 2A can include or be equivalent to an MMIC (monolithically integrated microwave circuit).

[0012] Radar microwave devices can be used in automotive, industrial, military, and / or defense applications for systems measuring ranges and speeds. Automotive applications might include advanced driver assistance systems, automatic speed control, collision avoidance systems, and similar technologies. Such systems can operate in the microwave frequency range and utilize FMCW (Frequency Modulated Continuous Wave) signals, for example, in the 24 GHz, 76 GHz, or 79 GHz frequency bands. The use of radar microwave systems can enable consistent and efficient vehicle operation. Efficient driving can, for example, reduce fuel consumption, thereby lowering CO2 emissions and saving energy.Additionally, the wear and tear on vehicle tires, brake discs, and brake pads can be reduced, thereby decreasing particulate matter pollution. Improved RF or radar systems, as described herein, can thus contribute to "green" technology solutions, i.e., climate-friendly solutions that provide lower energy consumption.

[0013] In some examples, the first RF chip 2A may contain at least one transmit channel (TX) designed to transmit RF signals via a TX antenna 14A. In some examples, the first RF chip 2A may contain at least one receive channel (RX) designed to receive RF signals via an RX antenna 16A. In some examples, the first RF chip 2A may contain at least one transmit (TX) and one receive (RX) channel, which can be referred to as a transmit-receiver chip (TRX). For simplicity, the example shown illustrates a TX antenna 14A and an RX antenna 16A. It is understood that in other examples, the first RF chip 2A may contain a different number of TX antennas 14A and / or RX antennas 16A, depending on the specific design of the RF device 100.In a non-restrictive example, the first RF chip 2A can contain four TX antennas 14A (or four TX channels) and four RX antennas 16A (or four RX channels).

[0014] The first RF chip 2A and the second RF chip 2B can be interconnected and cascaded to form a cascaded RF system. For example, the first RF chip 2A and the second RF chip 2B can be arranged on a common printed circuit board (PCB). The power combiner 8 and / or the power divider 20 can also be arranged on the PCB. Cascading multiple RF transceiver chips can increase the number of transmit and receive channels and thus the number of virtual array elements, thereby improving target acquisition and resolution, which may be necessary for certain applications such as Level 4 and Level 5 autonomous driving. The RF chips 2A and 2B can be synchronized to operate the cascaded RF system 100 as a single RF system in which each of the RF channels can have a predefined phase relationship to the others.To achieve proper synchronization between RF chips 2A and 2B, specific signals can be exchanged between the first RF chip 2A and the second RF chip 2B. In this context, the combined local oscillator signal 10 can be shared between the first RF chip 2A and the second RF chip 2B. In other words, both RF chips 2A and 2B can use the combined local oscillator signal 10 for operations such as signal transmission or mixing with received signals. For example, the combined local oscillator signal 10 can be mixed with an RF signal received via the receiving antenna 16A using a mixer 18A to convert the frequency of the received RF signal into a more manageable range. Specifically, an incoming RF signal from the receiving antenna 16A can be mixed with the combined local oscillator signal 10 to produce an intermediate frequency (IF) signal.The combined local oscillator signal 10 can be used to shift the frequency of the received RF signal into a frequency range that can be easily processed by the receiver and the subsequent processing stages of the RF device 100. The combined local oscillator signal 10 can be, or contain, a mm-wave LO signal. In some applications, the combined local oscillator signal 10 can contain, or be, an FMCW signal with a variety of frequency ramps.

[0015] As mentioned earlier, the first local oscillator signal 6A and the second local oscillator signal 6B can exhibit identical frequency responses during an operating time interval. The frequency response of a signal can refer to how a signal changes or varies with respect to its frequency or frequency content over time. In other words, it can describe how the frequency components of the signal evolve or shift over time. For example, the frequency response of the local oscillator signals 6A and 6B can include one or more frequency ramps with a start frequency and a stop frequency during the operating time interval that are the same for both local oscillator signals 6A and 6B. Specifically, the first local oscillator 4A and the second local oscillator 4B can be controlled to generate and output identical local oscillator signals.This means that possible differences between the first local oscillator signal 6A and the second oscillator signal 6B may be unintentional and may result, for example, from tolerances or inaccuracies in the manufacture of the RF device 100 or its components. For example, identical frequency response may include the first local oscillator signal 6A and the second local oscillator signal 6B having different amplitudes. Similarly, identical frequency response may include the first local oscillator signal 6A and the second local oscillator signal 6B being identical except for a phase difference. In particular, the phase difference between the first local oscillator signal 6A and the second local oscillator signal 6B may be constant.For example, the constant phase difference can be smaller than approximately π / 3, or smaller than approximately π / 4, or smaller than approximately π / 5, or smaller than approximately π / 6, or smaller than approximately π / 7, or smaller than approximately π / 8. The generation of the first local oscillator signal 6A can be independent of the generation of the second local oscillator signal 6B, and vice versa. This is also evident from [reference missing]. Fig. 1 shows where the first local oscillator 4A receives no input from the second local oscillator 4B and vice versa.

[0016] The first local oscillator signal 6A and the second local oscillator signal 6B can be based on the same reference clock. In this context, the RF device 100 can include at least one local oscillator or a crystal oscillator (not illustrated) designed to generate the reference clock and provide it to the first RF chip 2A and the second RF chip 2B. In one example, a local oscillator and / or a crystal oscillator can be located external to the first RF chip 2A and external to the second RF chip 2B. In another example, a local oscillator and / or a crystal oscillator can be located within or contained in the first RF chip 2A. In general, the frequency of the first local oscillator signal 6A and / or the frequency of the second local oscillator signal 6B can be higher than the frequency of the reference clock.In particular, the frequency of the first local oscillator signal 6A and / or the frequency of the second local oscillator signal 6B can be changed by a factor of approximately 10. 2 up to about 10 4 must be higher than the frequency of the reference clock. In a non-restrictive and exemplary case, the reference clock can have a frequency of approximately 50 MHz.

[0017] By combining the first local oscillator signal 6A and the second local oscillator signal 6B to form the combined local oscillator signal 10, the signal power of the local oscillator signal can be increased. That is, the signal power of the combined local oscillator signal 10 can be greater than the signal power of the first local oscillator signal 6A and greater than the signal power of the second local oscillator signal 6B. For example, the signal power of the combined local oscillator signal 10 can increase by approximately +6 dB if the first local oscillator signal 6A and the second local oscillator signal 6B are combined in phase. For this purpose, the signal paths from the RF chips 2A and 2B to the power combiner 8 should be of equal length to ensure the smallest possible phase difference.In this context, the RF device 100 can include a first signal path for transmitting the first local oscillator signal 6A from a local oscillator output 22A of the first RF chip 2A to a first local oscillator input 24A of the power combiner 8, and a second signal path for transmitting the second local oscillator signal 6B from a local oscillator output 22B of the second RF chip 2B to a second local oscillator input 24B of the power combiner 8. In examples, the signal paths can extend along a PCB on which the RF chips 2A and 2B can be mounted. To ensure the smallest possible phase difference between the first local oscillator signal 6A and the second local oscillator signal 6B at the inputs 24A and 24B of the combiner 8, the lengths of the first and second signal paths should be similar or equal.

[0018] In some examples, achieving the smallest possible phase difference between the first local oscillator signal 6A and the second local oscillator signal 6B at inputs 24A and 24B of the combiner 8 can be problematic. In such a case, at least one of the first RF chip 2A or the second RF chip 2B can contain a phase shifter placed between the local oscillator and the output of the respective RF chip. In the illustrated example, the first RF chip 2A can contain a first phase shifter 30A and the second RF chip 2B a second phase shifter 30B. The phase shifter(s) can be designed to compensate for a phase difference between the first local oscillator signal 6A and the second local oscillator signal 6B. In a non-restrictive example, a phase shifter can contain or be equivalent to an IQ modulator.

[0019] In the illustrated example, the RF device 100 can optionally include a power divider 20, which can be coupled to the power combiner 8 and is designed to split the combined local oscillator signal 10 received from the power combiner 8 into a first split local oscillator signal 26A for the first RF chip 2A and a second split local oscillator signal 26B for the second RF chip 2B. The RF device 100 can include a third signal path to transmit the first split local oscillator signal 26A from an output 28A of the power divider 20 to the input 12A of the first RF chip 2A, and a fourth signal path to transmit the second split local oscillator signal 26B from an output 28B of the power divider 20 to the input 12B of the second RF chip 2B. In particular, the length of the third signal path and the length of the fourth signal path can be the same.Due to the equal lengths of the third and fourth signal paths, the first RF chip 2A and the second RF chip 2B can each receive the same local oscillator signal from the power divider 20, thus enabling operation of the first RF chip 2A and the second RF chip 2B based on the same local oscillator signal. Specifically, the same local oscillator signal can be received at the RF inputs 12A and 12B of RF chips 2A and 2B with the same phase, ensuring coherence between RF chips 2A and 2B. For example, it is therefore possible for all RX channels to convert received signals from RF to baseband with the same phase. Furthermore, since the length of the local oscillator signal distribution can be the same for each RF chip, temperature effects can affect each RF chip equally, thereby reducing temperature-induced phase variations.

[0020] It should be noted that the power divider 20 of the RF device 100 can be considered optional. In another example, the RF device 100 does not necessarily include the power divider 20, and the combined local oscillator signal 10 can be transmitted directly from the power combiner 8 to the inputs 12A and 12B of the RF chips 2A and 2B. Similar to the examples that include the power divider 20, the length of the signal path between the power combiner 8 and the RF chips 2A and 2B can be chosen to provide the smallest possible phase differences.In this context, the RF device 100 can include a first signal path to transmit the first local oscillator signal 6A from the local oscillator output 22A of the first RF chip 2A to the first local oscillator input 24A of the power combiner 8, a second signal path to transmit the second local oscillator signal 6B from the local oscillator output 22B of the second RF chip 2B to the second local oscillator input 24B of the power combiner 8, a third signal path to transmit the combined local oscillator signal 10 from the power combiner 8 to the input 12A of the first RF chip 2A, and a fourth signal path to transmit the combined local oscillator signal 10 from the power combiner 8 to the input 12B of the second RF chip 2B.The power combiner 8, the first signal path, the second signal path, the third signal path, and the fourth signal path can be configured such that a phase of the combined local oscillator signal 10 at input 12A of the first RF chip 2A is the same as a phase of the combined local oscillator signal 10 at input 12B of the second RF chip 2B. For example, at least one internal structure of the power combiner 8, a length of the first signal path, a length of the second signal path, a length of the third signal path, a length of the fourth signal path, or a relative arrangement between the RF chips 2A, 2B, and the power combiner 8 can be adapted or chosen to achieve a similarity or equality of phases.

[0021] As mentioned previously, in some examples, the first RF chip 2A, the second RF chip 2B, the power combiner 8, and the power divider 20 can be arranged on the same PCB (or PCB laminate). In other examples, the first RF chip 2A, the second RF chip 2B, the power combiner 8, and the power divider 20 can be integrated into the same semiconductor package. In this context, a substrate can be integrated into the semiconductor package, with the aforementioned components (and also the signal paths that couple these components, as previously discussed) being arranged on the substrate. The RF device 100 can thus contain or correspond to a multi-chip package. A multi-chip package can be viewed as a collective assembly of several separate semiconductor chips (or semiconductor dies) and other optional electronic components.In some examples, the encapsulation or molding of multiple semiconductor chips and the creation of electrical redistributions can be part of a multi-chip package. A package can provide means for connecting the semiconductor package to its external environment (e.g., a printed circuit board (PCB)) via suitable electrical connection elements (e.g., leads, pads, balls, pins, or the like). Accordingly, the RF device 100, which is implemented as a multi-chip package, can include at least one external connection element (not illustrated) designed to mechanically and electrically connect the multi-chip package to, for example, a PCB (not illustrated). Furthermore, a package can optionally provide means for protecting its components against threats such as mechanical shock, chemical contamination, moisture, light exposure, or the like.In this respect, the RF device 100 designed in the form of a multi-chip package can comprise a chip package housing, wherein the first RF chip 2A, the second RF chip 2B, the power combiner 8, the power divider 20 and the signal paths electrically coupling these components can be encapsulated in the chip package housing.

[0022] In the example of the Fig. Figure 1 shows an exemplary number of two RF chips 2A and 2B for simplicity. However, it is understood that the RF device 100 can contain additional RF chips, the number and arrangement of which may depend on the specific design of the RF device 100. Such additional RF chips may incorporate some or all of the features of the RF chips 2A and 2B, as described above. In examples, the power combiner 8 may be configured to provide the combined local oscillator signal 10 to at least one of the additional RF chips of the RF device 100. Alternatively or additionally, local oscillator signals generated by local oscillators of additional RF chips may also be used to generate a combined local oscillator signal.In particular, the RF device 100 can include a third RF chip (not illustrated) containing a third local oscillator designed to generate and output a third local oscillator signal during the operating time interval. The first local oscillator signal 6A, the second local oscillator signal 6B, and the third local oscillator signal can have the same frequency response during the operating time interval. The power combiner 8 can be designed to combine the first local oscillator signal 6A, the second local oscillator signal 6B, and the third local oscillator signal into a combined local oscillator signal and output the combined local oscillator signal to an input of the first RF chip 2A, an input of the second RF chip 2B, and an input of the third RF chip.

[0023] It should be noted that the RF device can contain 100 additional components, which are located in Fig. 1. For the sake of simplicity, the details are not shown. For example, the RF device 100 can contain a 3D waveguide antenna, which can be coupled to at least one of the first RF chip 2A or the second RF chip 2B. In addition, the RF chips 2A and 2B can contain additional electronic circuits 46A and 46B, e.g., for processing transmit and / or receive RF signals in an analog and / or digital domain. For the sake of simplicity, details of the additional electronic circuits 46A and 46B are not explicitly shown and are discussed in the context of the example of Fig. 1.

[0024] The cascaded RF device 100 of the Fig. 1 may be superior to other cascaded RF devices in several ways. One example of another cascaded RF device 200 is in Fig. Figure 2 illustrates schematically. The RF device 200 can have similar components to those previously mentioned in connection with Fig. 1 were described. In the example of the Fig. 2. A local oscillator 4A of a first RF chip 2A can generate a local oscillator signal 6 and output it at an output 22A of the first RF chip 2A. A power divider 20 can be configured to split the local oscillator signal 6 received by the first RF chip 2A into a first split local oscillator signal 26A for the first RF chip 2A and a second split local oscillator signal 26B for the second RF chip 2B. That is, the local oscillator signal 6 generated by the first RF chip 2A is self-feeding to itself and to the second RF chip 2B. In examples, the first RF chip 2A can be called the primary RF chip (or master), while the second RF chip 2B can be called the secondary RF chip (or slave).The RF device 200 does not include a power combiner designed to combine local oscillator signals from both RF chips 2A and 2B into a combined local oscillator signal that can be input to and used by both RF chips 2A and 2B.

[0025] The RF device 100 of the Fig. 1 can the RF device 200 of the Fig. 2 is superior in that it can provide a higher signal power of the local oscillator signal. A signal power of the combined local oscillator signal 10 in Fig. 1 can be higher than the signal power of the local oscillator signal 6 in Fig. 2. When the first local oscillator signal 6A and the second local oscillator signal 6B are combined in phase, the signal power of the combined local oscillator signal 10 can increase by approximately +6 dB. Even with a phase difference between the local oscillator signals 6A and 6B, the signal power can be increased when the local oscillator signals 6A and 6B are combined, as described in the following. Fig. Figure 1 shows and describes this. For example, a phase difference of approximately 40 degrees between the local oscillator signals 6A and 6B at the power combiner 8 can still lead to an increase in signal power of approximately +5.5 dB. That is, even with a phase difference of approximately 40 degrees, the signal power of the combined local oscillator signal 10 can still be approximately +5.5 dB higher than if only one RF chip provides a local oscillator signal, as shown in Figure 1. Fig. 2 shown. Since in the example the Fig. Since both RF chips 2A and 2B can generate and output a local oscillator signal, each of the RF chips 2A and 2B can be programmed to operate as the primary RF chip of the RF device 100. That is, in the example of the Fig. 1. The RF chips 2A and 2B are not necessarily distinguished as primary and secondary RF chips. It is understood that the RF device 100 may additionally contain secondary RF chips that can receive the combined local oscillator signal 10 for operational purposes, but which do not necessarily have to contribute to the generation of the combined local oscillator signal 10.

[0026] In the example of Fig. 2. A guaranteed minimum output power of the primary local oscillator signal 6 and a required minimum input power at input 12A of the secondary RF chip 2B can limit the maximum number of RF chips used in the device 200 and also the maximum possible distance between the RF chips. In addition, the use of inexpensive PCB laminates can lead to higher attenuation of the local oscillator signal. In contrast, the device 200 of Fig. 2, as already discussed, provide a higher signal power of the local oscillator signal. In this way, the power budget of the local oscillator between the RF chips of the device 200 can be improved, which allows the use of less expensive PCB laminates and / or a higher number of RF chips in the RF device 100.

[0027] The RF device 100 of the Fig. 1. The RF device 200 can be used. Fig. 2 surpasses the previous method in that it can reduce the phase noise. When combining the first local oscillator signal 6A and the second local oscillator signal 6B to form the combined local oscillator signal 10, the relative increase in signal power can be greater than the relative increase in phase noise. As discussed previously, when combining two local oscillator signals 6A and 6B, the signal power of the combined local oscillator signal 10 can increase by up to approximately +6 dB. Simultaneously, the phase noise of the combined local oscillator signal 10 can only increase by approximately +3 dB. Accordingly, combining the local oscillator signals 6A and 6B can lead to an improvement in phase noise of approximately -3 dB.

[0028] Fig. Figure 3 illustrates a flowchart of a method for operating a cascaded RF device according to the disclosure. The method can be used for operating cascaded RF devices as described above and can therefore be read in conjunction with the previous figures. The method of Fig. Section 3 is described in general terms to qualitatively specify aspects of the revelation. It is understood that the procedure may also include further aspects. For example, the procedure may extend to any of the aspects described in connection with other examples according to the revelation.

[0029] In 32, a first local oscillator signal can be generated and output by a first local oscillator of a first RF chip during an operating time interval. In 34, a second local oscillator signal can be generated and output by a second local oscillator of a second RF chip during the operating time interval. In 36, the first local oscillator signal and the second local oscillator signal can be combined into a combined local oscillator signal by a power combiner. In 38, the combined local oscillator signal can be output by the power combiner to an input of the first RF chip and to an input of the second RF chip. The first local oscillator signal and the second local oscillator signal can have the same frequency response during the operating time interval.

[0030] Fig. Figure 4 illustrates a flowchart of a process for manufacturing a cascaded RF device according to the disclosure. The process can be used to manufacture cascaded RF devices as previously described and can thus be read in conjunction with the preceding figures. The process of Fig. Section 4 is described in general terms to qualitatively specify aspects of the revelation. It is understood that the procedure may include further aspects. For example, the procedure may be extended to include any of the aspects described in connection with other examples according to the revelation.

[0031] At 40, a first RF chip containing a first local oscillator designed to generate and output a first local oscillator signal during an operating time interval can be arranged. At 42, a second RF chip containing a second local oscillator designed to generate and output a second local oscillator signal during the operating time interval can be arranged. At 44, a power combiner designed to combine the first local oscillator signal and the second local oscillator signal into a combined local oscillator signal and to output the combined local oscillator signal to an input of the first RF chip and to an input of the second RF chip. The first local oscillator signal and the second local oscillator signal can have the same frequency response during the operating time interval. EXAMPLES

[0032] The examples described herein provide cascaded RF devices and methods for operating and manufacturing cascaded RF devices.

[0033] Example 1 is a cascaded radio frequency (RF) device comprising: a first RF chip including a first local oscillator designed to generate and output a first local oscillator signal during an operating time interval; a second RF chip including a second local oscillator designed to generate and output a second local oscillator signal during the operating time interval; and a power combiner designed to combine the first local oscillator signal and the second local oscillator signal into a combined local oscillator signal and to output the combined local oscillator signal to an input of the first RF chip and to an input of the second RF chip, wherein the first local oscillator signal and the second local oscillator signal have the same frequency response during the operating time interval.

[0034] Example 2 is a cascaded RF device according to Example 1, wherein the frequency response includes a frequency ramp with a start frequency and a stop frequency during the operating time interval.

[0035] Example 3 is a cascaded RF device according to Example 1 or 2, in which the first local oscillator and the second local oscillator are controlled to generate and output the same local oscillator signal.

[0036] Example 4 is a cascaded RF device according to one of the preceding examples, wherein the first local oscillator signal and the second local oscillator signal are identical except for a phase difference.

[0037] Example 5 is a cascaded RF device according to one of the preceding examples, wherein a phase difference between the first local oscillator signal and the second local oscillator signal is constant.

[0038] Example 6 is a cascaded RF device according to Example 5, where the constant phase difference is less than π / 3.

[0039] Example 7 is a cascaded RF device according to one of the preceding examples, wherein the first local oscillator signal and the second local oscillator signal are based on the same reference clock.

[0040] Example 8 is a cascaded RF device according to Example 7, further comprising: at least one local oscillator or a crystal oscillator arranged externally to the first RF chip and externally to the second RF chip and designed to generate the reference clock and to provide the reference clock to the first RF chip and the second RF chip.

[0041] Example 9 is a cascaded RF device according to Example 7, further comprising: at least one local oscillator or a crystal oscillator designed in the first RF chip to generate the reference clock and to provide the reference clock to the first RF chip and the second RF chip.

[0042] Example 10 is a cascaded RF device according to any of the preceding examples, further comprising: a first signal path for transmitting the first local oscillator signal from an output of the first RF chip to a first input of the power combiner; and a second signal path for transmitting the second local oscillator signal from an output of the second RF chip to a second input of the power combiner, wherein the length of the first signal path and the length of the second signal path are equal.

[0043] Example 11 is a cascaded RF device according to any of the preceding examples, further comprising: a first signal path to transmit the first local oscillator signal from an output of the first RF chip to a first input of the power combiner; a second signal path to transmit the second local oscillator signal from an output of the second RF chip to a second input of the power combiner; a third signal path to transmit the combined local oscillator signal from the power combiner to a first input of the first RF chip;and a fourth signal path to transmit the combined local oscillator signal from the power combiner to a second input of the second RF chip, wherein the power combiner, the first signal path, the second signal path, the third signal path and the fourth signal path are designed such that a phase of the combined local oscillator signal at the first input of the first RF chip is the same as a phase of the combined local oscillator signal at the second input of the second RF chip.

[0044] Example 12 is a cascaded RF device according to any one of Examples 1 to 10, further comprising: a power divider coupled to the power combiner and designed to divide the combined local oscillator signal received from the power combiner into a first split local oscillator signal for the first RF chip and a second split local oscillator signal for the second RF chip.

[0045] Example 13 is a cascaded RF device according to Example 12, further comprising: a third signal path to transfer the first split local oscillator signal from an output of the power divider to an input of the first RF chip; and a fourth signal path to transfer the second split local oscillator signal from an output of the power divider to an input of the second RF chip, wherein the length of the third signal path and the length of the fourth signal path are the same.

[0046] Example 14 is a cascaded RF device according to one of the preceding examples, wherein when the first local oscillator signal and the second local oscillator signal are combined to form the combined local oscillator signal, the relative increase in signal power is greater than the relative increase in phase noise.

[0047] Example 15 is a cascaded RF device according to one of the preceding examples, wherein: the first RF chip and the second RF chip are integrated in the same semiconductor package and the power combiner is located in the semiconductor package.

[0048] Example 16 is a cascaded RF device according to one of the preceding examples, wherein both the first RF chip and the second RF chip are programmed to operate as the primary RF chip of the cascaded RF device.

[0049] Example 17 is a cascaded RF device according to any of the preceding examples, wherein: at least one of the first RF chip or the second RF chip comprises a phase shifter designed between the local oscillator and an output of the respective RF chip, and the phase shifter is designed to compensate for a phase difference between the first local oscillator signal and the second local oscillator signal.

[0050] Example 18 is a cascaded RF device according to one of the preceding examples, wherein the power combiner is designed to provide the combined local oscillator signal to a third RF chip of the cascaded RF device.

[0051] Example 19 is a cascaded RF device according to any of the preceding examples, further comprising: a third RF chip comprising a third local oscillator designed to generate and output a third local oscillator signal during the operating time interval, wherein the power combiner is designed to combine the first local oscillator signal, the second local oscillator signal and the third local oscillator signal into a combined local oscillator signal and to output the combined local oscillator signal to an input of the first RF chip, to an input of the second RF chip and to an input of the third RF chip, wherein the first local oscillator signal, the second local oscillator signal and the third local oscillator signal have the same frequency response during the operating time interval.

[0052] Example 20 is a cascaded RF device according to one of the preceding examples, further comprising: a 3D waveguide antenna coupled to at least the first RF chip or the second RF chip.

[0053] Example 21 is a method for operating a cascaded RF device, wherein the method comprises: generating and outputting a first local oscillator signal by a first local oscillator of a first RF chip during an operating time interval; generating and outputting a second local oscillator signal by a second local oscillator of a second RF chip during the operating time interval; combining the first local oscillator signal and the second local oscillator signal by a power combiner to form a combined local oscillator signal; and outputting the combined local oscillator signal by the power combiner to an input of the first RF chip and to an input of the second RF chip, wherein the first local oscillator signal and the second local oscillator signal have the same frequency response during the operating time interval.

[0054] Example 22 is a method for manufacturing a cascaded RF device, wherein the method comprises: arranging a first RF chip comprising a first local oscillator designed to generate and output a first local oscillator signal during an operating time interval; arranging a second RF chip comprising a second local oscillator designed to generate and output a second local oscillator signal during the operating time interval;and arranging a power combiner designed to combine the first local oscillator signal and the second local oscillator signal into a combined local oscillator signal and to output the combined local oscillator signal to an input of the first RF chip and to an input of the second RF chip, wherein the first local oscillator signal and the second local oscillator signal have the same frequency response during the operating time interval.

[0055] As used in this description, the terms "connected," "coupled," "electrically connected," and / or "electrically coupled" do not necessarily mean that elements must be directly connected or coupled to each other. Intermediate elements may be provided between the "connected," "coupled," "electrically connected," or "electrically coupled" elements.

[0056] Where the terms “having”, “containing”, “including”, “with”, or variations thereof are used in the detailed description or in the claims, these terms shall be understood to be broad in a similar way to the term “comprising”. That is to say, as used herein, the expressions “having”, “containing”, “including”, “with”, “comprising”, or similar are open terms that indicate the presence of specified elements or features but do not exclude additional elements or features. The articles “a”, “an”, and “the” shall be understood to include both the plural and the singular unless the context clearly indicates otherwise.

[0057] Furthermore, the terms "exemplary" and "example" are used herein to clarify an example, instance, or illustration. Any aspect or design described herein as "exemplary" or "example" is not necessarily to be understood as advantageous over other aspects or designs. Rather, the use of the words "exemplary" and "example" is intended to illustrate concepts concretely. As used in this application, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or." That is to say, unless otherwise stated or evident from the context, "X uses A or B" refers to each of the natural, inclusive permutations. That is, if X uses A, X uses B, or X uses both A and B, then the condition "X uses A or B" is satisfied in each of the preceding instances.In addition, the articles “a” and “an”, as used in this application and the attached claims, can generally be interpreted as meaning “one or more”, unless otherwise specified or it is clear from the context that they refer to a singular form. Furthermore, at least one of A and B or similar generally means A or B or both A and B.

[0058] Although specific examples have been illustrated and described herein, the person skilled in the art will recognize that the specific examples shown and described can be replaced by a multitude of alternative and / or equivalent embodiments without departing from the scope of the present invention. This application is intended to cover all adaptations or variations of the specific examples discussed herein. Therefore, the present invention is to be limited only by the claims and their equivalents.

[0059] It should be noted that the methods and devices, including their preferred embodiments, as described in this document, can be used alone or in combination with the other methods and devices disclosed herein. Furthermore, the features described in connection with a device are also applicable to a corresponding method, and vice versa. In addition, all aspects of the methods and devices described in this document can be combined as desired. In particular, the features of the claims can be combined with one another in any way.

[0060] It should be noted that the description and drawings merely illustrate the principles of the proposed methods and systems. A person skilled in the art will be able to implement various arrangements which, although not expressly described or shown herein, embody the principles of the invention and are contained within its spirit and scope. Furthermore, all examples and embodiments outlined in this document are expressly intended only for explanatory purposes, to assist the reader in understanding the principles of the proposed methods and systems. Moreover, all explanations of principles, aspects, and embodiments of the invention provided herein, as well as specific examples thereof, are also intended to encompass equivalents.

Claims

[1] Cascaded radio frequency (RF) device comprising: a first RF chip (2A) comprising a first local oscillator (4A) designed to generate and output a first local oscillator signal (6A) during an operating time interval; a second RF chip (2B) comprising a second local oscillator (4B) designed to generate and output a second local oscillator signal (6B) during the operating time interval; and a power combiner (8) designed to combine the first local oscillator signal (6A) and the second local oscillator signal (6B) into a combined local oscillator signal (10) and to output the combined local oscillator signal (10) to an input of the first RF chip (2A) and to an input of the second RF chip (2B), wherein the first local oscillator signal (6A) and the second local oscillator signal (6B) exhibit the same frequency response during the operating time interval. [2] Cascaded RF device according to claim 1, wherein the frequency response comprises a frequency ramp with a start frequency and a stop frequency during the operating time interval. [3] Cascaded RF device according to claim 1 or 2, wherein the first local oscillator (4A) and the second local oscillator (4B) are controlled to generate and output the same local oscillator signal. [4] Cascaded RF device according to one of the preceding claims, wherein the first local oscillator signal (6A) and the second local oscillator signal (6B) are identical except for a phase difference. [5] Cascaded RF device according to one of the preceding claims, wherein a phase difference between the first local oscillator signal (6A) and the second local oscillator signal (6B) is constant. [6] Cascaded RF device according to claim 5, wherein the constant phase difference is less than π / 3. [7] Cascaded RF device according to one of the preceding claims, wherein the first local oscillator signal (6A) and the second local oscillator signal (6B) are based on the same reference clock. [8] Cascaded RF device according to claim 7, further comprising: at least one local oscillator or crystal oscillator located externally to the first RF chip (2A) and externally to the second RF chip (2B) and designed to generate the reference clock and to provide the reference clock to the first RF chip (2A) and the second RF chip (2B). [9] Cascaded RF device according to claim 7, further comprising: at least one local oscillator or crystal oscillator located in the first RF chip (2A) and designed to generate the reference clock and to provide the reference clock to the first RF chip (2A) and the second RF chip (2B). [10] Cascaded RF device according to any one of the preceding claims, further comprising: a first signal path for transmitting the first local oscillator signal (6A) from a local oscillator output (22A) of the first RF chip (2A) to a first local oscillator input (24A) of the power combiner (8); and a second signal path for transmitting the second local oscillator signal (6B) from a local oscillator output (22B) of the second RF chip (2B) to a second local oscillator input (24B) of the power combiner (8), where the length of the first signal path and the length of the second signal path are equal. [11] Cascaded RF device according to any one of the preceding claims, further comprising: a first signal path for transmitting the first local oscillator signal (6A) from a local oscillator output (22A) of the first RF chip (2A) to a first local oscillator input (24A) of the power combiner (8); a second signal path for transmitting the second local oscillator signal (6B) from a local oscillator output (22B) of the second RF chip (2B) to a second local oscillator input (24B) of the power combiner (8); a third signal path for transmitting the combined local oscillator signal (10) from the power combiner (8) to a first input (12A) of the first RF chip (2A); and a fourth signal path for transmitting the combined local oscillator signal (10) from the power combiner (8) to a second input (12B) of the second RF chip (2B), wherein the power combiner (8), the first signal path, the second signal path, the third signal path and the fourth signal path are designed such that a phase of the combined local oscillator signal (10) at the first input (12A) of the first RF chip (2A) is the same as a phase of the combined local oscillator signal (10) at the second input (12B) of the second RF chip (2B). [12] Cascaded RF device according to any one of claims 1 to 10, further comprising: a power divider (20) coupled to the power combiner (8) and designed to divide the combined local oscillator signal (10) received from the power combiner (8) into a first split local oscillator signal (26A) for the first RF chip (2A) and a second split local oscillator signal (26B) for the second RF chip (2B). [13] Cascaded RF device according to claim 12, further comprising: a third signal path for transmitting the first split local oscillator signal (26A) from an output (28A) of the power divider (20) to an input (12A) of the first RF chip (2A); and a fourth signal path for transmitting the second split local oscillator signal (26B) from an output (28B) of the power divider (20) to an input (12B) of the second RF chip (2B), where the length of the third signal path and the length of the fourth signal path are equal. [14] Cascaded RF device according to one of the preceding claims, wherein when combining the first local oscillator signal (6A) and the second local oscillator signal (6B) to form the combined local oscillator signal (10) the relative increase in signal power is greater than the relative increase in phase noise. [15] Cascaded RF device according to any one of the preceding claims, wherein: the first RF chip (2A) and the second RF chip (2B) are integrated in the same semiconductor package, and the power combiner (8) is arranged in the semiconductor package. [16] Cascaded RF device according to one of the preceding claims, wherein the first RF chip (2A) and the second RF chip (2B) are each programmed to operate as the primary RF chip of the cascaded RF device. [17] Cascaded RF device according to any of the preceding claims, wherein: at least one of the first RF chip (2A) or the second RF chip (2B) comprises a phase shifter (30) arranged between the local oscillator (4) and a local oscillator output (22) of the respective RF chip (2), and the phase shifter (30) is designed to compensate for a phase difference between the first local oscillator signal (6A) and the second local oscillator signal (6B). [18] Cascaded RF device according to one of the preceding claims, wherein the power combiner (8) is configured to provide the combined local oscillator signal (10) to a third RF chip of the cascaded RF device. [19] Cascaded RF device according to any one of the preceding claims, further comprising a third RF chip comprising a third local oscillator designed to generate and output a third local oscillator signal during the operating time interval, wherein the power combiner (8) is designed to combine the first local oscillator signal (6A), the second local oscillator signal (6B) and the third local oscillator signal into a combined local oscillator signal and to output the combined local oscillator signal to an input (12A) of the first RF chip (2A), to an input (12B) of the second RF chip (2B) and to an input of the third RF chip, wherein the first local oscillator signal (6A), the second local oscillator signal (6B) and the third local oscillator signal exhibit the same frequency behavior during the operating time interval. [20] Cascaded RF device according to any one of the preceding claims, further comprising: a 3D waveguide antenna coupled to at least one of the first RF chip (2A) or the second RF chip (2B). [21] Method for operating a cascaded RF device, the method comprising: Generating and outputting a first local oscillator signal (6A) by a first local oscillator (4A) of a first RF chip (2A) during an operating time interval; Generating and outputting a second local oscillator signal (6B) by a second local oscillator (4B) of a second RF chip (2B) during the operating time interval; Combine, by means of a power combiner (8), the first local oscillator signal (6A) and the second local oscillator signal (6B) to form a combined local oscillator signal (10); and Output, through the power combiner (8), of the combined local oscillator signal (10) to an input (12A) of the first RF chip (2A) and to an input (12B) of the second RF chip (2B), wherein the first local oscillator signal (6A) and the second local oscillator signal (6B) exhibit the same frequency response during the operating time interval. [22] Method for manufacturing a cascaded RF device, the method comprising: Arranging a first RF chip (2A) comprising a first local oscillator (4A) designed to generate and output a first local oscillator signal (6A) during an operating time interval; Arranging a second RF chip (2B) comprising a second local oscillator (4B) designed to generate and output a second local oscillator signal (6B) during the operating time interval; and Arranging a power combiner (8) designed to combine the first local oscillator signal (6A) and the second local oscillator signal (6B) into a combined local oscillator signal (10) and to output the combined local oscillator signal (10) to an input (12A) of the first RF chip (2A) and to an input (12B) of the second RF chip (2B), wherein the first local oscillator signal (6A) and the second local oscillator signal (6B) have the same frequency response during the operating time interval.

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