Local oscillator filtering in mixers

Abstract

An integrated circuit is described that selectively filters out common-mode and differential signals. The integrated circuit may include an RF receiver having a mixer that converts signals between a frequency band at RF and a second frequency band based at least in part on a second signal, the second frequency band being smaller than the frequency band. The mixer may further include an input port that receives the second signal and a filter circuit electrically coupled in parallel with the input port that filters out common-mode signals above a threshold frequency and filters out differential signals below a threshold frequency. For example, the filter circuit may include a half-wave transmission line. It should be noted that the mixer may convert differential signals to common-mode signals below a threshold frequency and convert common-mode signals to differential signals above a threshold frequency.

Description

[Technical Field]

[0001] The present disclosure relates to techniques for encoding multiple-input multiple-output (MIMO) radar signals using Doppler code multiplexing. [Background technology]

[0002] To provide improved safety and convenience for transportation, many automobile manufacturers are equipping their vehicles with additional sensors and / or features. For example, autonomous vehicles typically include a wide variety of sensors, such as acoustic and / or electromagnetic sensors, that monitor the surrounding environment to detect other vehicles, people, animals, or obstacles. However, there are still challenges that degrade the performance of radar sensors in automotive applications.

[0003] In particular, in radio frequency (RF) receiver front ends, noise figure (NF) and input 1 dB compression point are typically key performance parameters. While good values ​​of both of these performance parameters are desirable, in practice, there are usually trade-offs. As a result, there are generally two approaches for designing RF receiver front ends: the low noise amplifier (LNA)-first approach and the mixer-first approach. These two configurations are shown in Figures 1 and 2, which present block diagrams illustrating existing RF receiver front ends. Placing the LNA first results in a larger signal at the mixer, which typically improves noise performance but may limit linearity. Alternatively, placing the mixer first typically improves linearity but may degrade noise performance.

[0004] In a mixer-first configuration, noise contributions include the RF input stage, the switching pair, and the noise-generating local oscillator (LO) amplifier. To reduce noise, a double-balanced mixer topology is usually used to cancel the LO signal at the output. However, compared to a single balanced-mixer topology, a double-balanced mixer is typically larger, consumes more power, and generates more switching-pair noise. Summary of the Invention [Means for solving the problem]

[0005] An embodiment of an integrated circuit is described. The integrated circuit includes an RF receiver having a mixer that converts signals between a frequency band at RF and a second frequency band that is based at least in part on a second signal (sometimes referred to as a "local oscillator" signal), the second frequency band being smaller than the frequency band. Further, the mixer includes an input port that receives the second signal, and a filter circuit electrically coupled in parallel with the input port that filters out common-mode signals above a threshold frequency and filters out differential signals below a threshold frequency.

[0006] It should be noted that the filter circuit may include a transmission line. For example, the transmission line may include a half-wave transmission line. In some embodiments, the transmission line may include a shielded microstrip transmission line.

[0007] Additionally, the mixer may be a down-conversion mixer that converts signals from the frequency band to a second frequency band, or alternatively, the mixer may be an up-conversion mixer that converts signals from a second frequency band to the frequency band.

[0008] Additionally, the RF receiver may include an amplifier that provides the second signal to the mixer.

[0009] Additionally, the signals in that frequency band may be single-ended signals, and the signals in the second frequency band may be differential signals.

[0010] In some embodiments, the mixer may convert a differential signal to a common mode signal below a threshold frequency and may convert a common mode signal to a differential signal above a threshold frequency.

[0011] Note that the second frequency band may be greater than DC.

[0012] Additionally, the mixer may include a balanced mixer.

[0013] Another embodiment provides an electronic device including an integrated circuit.

[0014] Another embodiment provides a method of mixing signals, the method including at least some of the operations being performed by an integrated circuit.

[0015] This Summary is presented for the purposes of illustrating some exemplary embodiments to aid in a basic understanding of some aspects of the subject matter described herein. Accordingly, it will be understood that the features described above are examples and should not be construed in any way as narrowing the scope or spirit of the subject matter described herein. Other features, aspects, and advantages of the subject matter described herein will become apparent from the following Detailed Description, Figures, and Claims. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a block diagram illustrating an example of a low noise amplifier (LNA)-first configuration in an existing radio frequency (RF) receiver front end. [Figure 2] FIG. 1 is a block diagram illustrating an example of a mixer-first configuration in an existing RF receiver front end. [Figure 3] 1 is a diagram illustrating an example of a vehicle equipped with a radar sensor according to some embodiments of the present disclosure. [Figure 4] FIG. 1 is a block diagram illustrating an example of a driver assistance system according to some embodiments of the present disclosure. [Figure 5] FIG. 1 is a block diagram illustrating an example of a radar system according to some embodiments of the present disclosure. [Figure 6] FIG. 1 is a block diagram illustrating an example of a radar system according to some embodiments of the present disclosure. [Figure 7] FIG. 2 is a block diagram illustrating an example of a down-conversion mixer according to some embodiments of the present disclosure. [Figure 8] FIG. 2 is a block diagram illustrating an example of an upconversion mixer according to some embodiments of the present disclosure. [Figure 9] FIG. 1 is a block diagram illustrating a double balanced mixer in an existing RF receiver front end. [Figure 10] 1 is a block diagram illustrating an existing RF receiver front end having a balun at the local oscillator (LO) input. [Figure 11] FIG. 1 is a block diagram illustrating an example of a half-wave transmission line according to some embodiments of the present disclosure. [Figure 12] FIG. 1 is a block diagram illustrating an example of a half-wave transmission line according to some embodiments of the present disclosure. [Figure 13] FIG. 1 is a block diagram illustrating an example of an RF receiver front end according to some embodiments of the present disclosure. [Figure 14] FIG. 1 is a block diagram illustrating an example of S-parameter insertion loss (S21) as a function of frequency for an RF receiver front end according to some embodiments of the present disclosure. [Figure 15]FIG. 1 is a block diagram illustrating an example of noise figure (NF) as a function of frequency for an RF receiver front end with and without a half-wavelength transmission line, in accordance with some embodiments of the present disclosure. [Figure 16] 1 is a flow diagram illustrating an example of a method for selective filtering according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0017] It should be noted that like reference numbers refer to corresponding parts throughout the drawings. Additionally, multiple instances of the same part are designated by a common prefix separated from the instance number by a dash.

[0018] An integrated circuit is described that selectively filters out common-mode and differential signals. The integrated circuit may include an RF receiver having a mixer (e.g., a downconversion mixer or an upconversion mixer) that converts signals between a frequency band at RF and a second frequency band based at least in part on a second signal, the second frequency band being smaller than the frequency band. Furthermore, the mixer may include an input port that receives the second signal and a filter circuit electrically coupled in parallel with the input port that filters out common-mode signals above a threshold frequency and filters out differential signals below a threshold frequency. For example, the filter circuit may include a transmission line, such as a half-wave transmission line. It should be noted that the mixer may convert differential signals to common-mode signals below a threshold frequency and convert common-mode signals to differential signals above a threshold frequency.

[0019] These circuit techniques can improve the performance of RF receivers by selectively filtering common-mode and differential signals. In particular, the RF receivers can have improved noise figures while maintaining high linearity. In addition, the area and power consumption of the RF receivers can be reduced. As a result, these circuit techniques can enable the use of MIMO and improve the performance of radar measurements performed using integrated circuits.

[0020] In the following description, a vehicle may include an automobile, a sport utility vehicle, a truck, a motorcycle, a train, an aircraft, a boat, or other type of transportation vehicle, however, in the following description, an automobile is used as an illustrative example of a vehicle.

[0021] Furthermore, in the following description, the vehicle may use one or more types of sensors to perform measurements related to objects in the surrounding environment. While a wide variety of types of sensors may be used, in the following description, a radar sensor is used as an illustrative example. The radar sensor may perform measurements using at least one of various modes of operation (such as pulsed wave or continuous wave) and may involve the use of one or more types of modulation (such as amplitude, frequency, and / or phase modulation). In some embodiments, a frequency-modulated continuous wave (FMCW) radar is used. Furthermore, the transmitted and received radar signals (e.g., having a carrier frequency within a radar frequency band, such as between 3 MHz and 100 GHz) may be generated and / or processed in the analog and / or digital domains.

[0022] Next, embodiments of the circuit technology will be described. FIG. 3 presents a diagram illustrating an example of a vehicle 110 equipped with an array of radar antennas, including an antenna 112 for short-range sensing (e.g., for parking assistance), an antenna 114 for medium-range sensing (e.g., for monitoring traffic jams and cut-in events), and an antenna 116 for long-range sensing (e.g., for adaptive cruise control and collision warning), each of which may be located behind the front bumper cover. An antenna 118 for short-range sensing (e.g., for backup assist) and an antenna 120 for medium-range sensing (e.g., for rear collision warning) may be located behind the back bumper cover. Additionally, an antenna 122 for short-range sensing (e.g., for blind spot monitoring and side obstacle detection) may be located behind the car fender. Each antenna and each set of antennas may be grouped into one or more arrays. Furthermore, each array may be controlled by a radar array controller 205 (FIG. 4). In some embodiments, a given set of antennas may perform multiple-input, multiple-output (MIMO) radar sensing. The type, number, and configuration of sensors in sensor arrangements for vehicles with driver assistance and autonomous driving functions vary. Vehicles may employ sensor arrangements to detect and measure distance / direction to objects within various detection zones, allowing the vehicle to navigate while avoiding other vehicles and obstacles. While the preceding description illustrates vehicle 110 with radar sensors, in other embodiments, vehicle 110 may include additional types of sensors, such as LiDAR, ultrasonic sensors, cameras, etc.

[0023] FIG. 4 presents a block diagram illustrating an example of a driver assistance system. The driver assistance system may include an electronic control unit (ECU) 210 at the center of a star topology, coupled to various sensors 212 and a radar array controller 214. However, other topologies may include serial, parallel, and hierarchical (tree) topologies. The radar array controller 214 may be coupled to transmit and receive antennas (e.g., within antenna 114) to transmit electromagnetic waves, receive reflections, and determine the spatial relationship of the vehicle to its surroundings. Additionally, the radar array controller 214 may be coupled to a carrier signal generator. In some embodiments, the radar array controller 214 may control the timing and sequence of operation of multiple carrier signal generators.

[0024] To provide automated parking assistance, ECU 210 may be coupled to a set of actuators, such as a turn signal actuator 216, a steering actuator 218, a braking actuator 220, and / or a throttle actuator 222. Additionally, ECU 210 may be coupled to an interactive user interface 224 for accepting user input and displaying various measurements and system status.

[0025] Using the user interface 224, sensors, and actuators, the ECU 210 may provide automatic parking, park assist, lane change assist, obstacle and blind spot detection, autonomous driving, and / or other desirable features. During operation of the vehicle 110 (FIG. 3), sensor measurements may be obtained by the ECU 210 and used by the ECU 210 to determine the status of the vehicle 110. Furthermore, the ECU 210 may act based on the status and input information to activate signaling and control transducers to coordinate and maintain the operation of the vehicle 110. For example, operations that may be provided by the ECU 210 include driver assistance functions such as automatic parking, lane following, automatic braking, and automated driving.

[0026] Additionally, to obtain measurements, ECU 210 may employ a MIMO radar system. Radar systems operate by emitting electromagnetic waves that propagate outward from a transmitting antenna, which then reflects the waves toward a receiving antenna. A reflector may be any moderately reflective object within the path of the emitted electromagnetic wave. By measuring the propagation time of the electromagnetic wave from the transmitting antenna to the reflector and back to the receiving antenna, the radar system can determine the distance to the reflector. Additionally, by measuring the Doppler shift of the electromagnetic wave, the radar system can determine the velocity of the reflector relative to vehicle 110 (FIG. 3). When multiple transmitting or receiving antennas are used, or when multiple measurements are taken at different locations, the radar system can determine the direction to the reflector and thereby track the location of the reflector relative to vehicle 110 (FIG. 3). With more advanced processing, multiple reflectors may be tracked. In some embodiments, the radar system may employ array processing to "scan" a directional beam of electromagnetic waves and build a circumferential image of the environment around vehicle 110 (FIG. 3). In general, pulsed and / or continuous wave implementations of radar systems may be implemented.

[0027] FIG. 5 presents a block diagram illustrating an example of a radar system 310 having a MIMO configuration in which J transmitters are collectively coupled to M transmit antennas 312 to transmit transmit signals 316, where J and M are nonzero integers. The M possible transmit signals 316 may reflect from one or more reflectors or targets 314 and be received as receive signals 318 via N receive antennas 320 coupled to P receivers, where N and P are nonzero integers. Each receiver may extract the amplitude and phase or propagation delay associated with each of the M transmit signals 316, thereby enabling the system to obtain N·M measurements (although only J·P of the measurements may be obtained simultaneously). The processing requirements associated with each receiver extracting the J measurements may be reduced through the use of time-division multiplexing and / or orthogonal coding. Furthermore, available antennas may be systematically multiplexed to available transmitters and receivers to collect a complete set of measurements for radar imaging.

[0028] FIG. 6 presents a block diagram illustrating an example of a radar transceiver circuit 410 (e.g., in the radar system 310 of FIG. 5). In some embodiments, the radar transceiver circuit 410 is implemented as an integrated circuit in a packaged chip. The radar transceiver circuit 410 may include a carrier signal (chirp) generator 412, a phase shifter 414 (and, more generally, an encoder circuit, which may implement Doppler code multiplexing), an amplifier 416, and / or a transmit antenna 312 that can transmit a signal 316 based at least in part on the output of the carrier signal generator 412. Additionally, the radar transceiver circuit 410 may include a receive antenna 320, a low-noise amplifier (LNA) 418, and / or a mixer 420 (which, in some embodiments, may implement Doppler code multiplexing). The mixer 420 may mix the received signal 318 detected by the receive antenna 312 with the signal from the carrier signal generator 412. Additionally, a low-noise amplifier 418 may be used to amplify the received signal 318 detected by the receive antenna 320. In some embodiments, the radar transceiver circuit 410 may include a sensitivity time controller and equalizer (not shown), a wideband (BB) filter 422, an analog-to-digital converter (ADC) 424, and / or a processor 426 (e.g., the ECU 210 and / or the radar array controller 214 of FIG. 4 ) to perform further processing (such as a Fourier transform) of the received signal. In some embodiments, the processor 426 and the low-noise amplifier 418 may be coupled for bidirectional communication.

[0029] Additionally, in some embodiments, the carrier signal generator 412 may be coupled to the radar array controller 214 (FIG. 4). The carrier signal generator 412 may include a chirp generator for generating an FMCW signal. The chip rate of the carrier signal generator 412 may be controlled by the radar array controller 214 (FIG. 4). In some embodiments, the carrier signal generator 412 may be deactivated by the radar array controller 214 (FIG. 4) to provide an unmodulated carrier signal. Furthermore, the carrier signal generator 412 may be implemented as a local oscillator (LO) signal generator, a fractional-N phase-locked loop (PLL) with a ΣΔ controller, or a direct digital synthesis generator.

[0030] Further, the carrier signal generator 412 may be coupled to the transmit antenna 312 via a phase shifter 414 and an amplifier 416. The carrier signal generator 412 may be coupled to the receive antenna 312 through a mixer 420 and a low-noise amplifier 418. In addition, the carrier signal generator 412 may generate a transmit signal (e.g., a chirp signal). The amplifier 416 may receive the transmit signal from the carrier signal generator 412, and a transmit signal 316 corresponding to the transmit signal from the carrier signal generator 412 may be transmitted using the transmit antenna 312.

[0031] In some embodiments, the radar transmitter may include a phase rotator, a binary phase modulator, a variable gain amplifier, a switch, a power amplifier driver, a power amplifier, and / or a digital signal processor (DSP). Additionally, in some embodiments, the radar transmitter may include a digital controller. This digital controller may be included in the DSP or may be a separate component. Furthermore, the phase rotator may be used for digital phase modulation. Additionally, the radar transmitter may use a wave modulation power amplifier in a digital envelope modulation technique.

[0032] As previously explained, noise is still often a problem in existing RF receiver front-ends. In the disclosed circuit technique, the LO signal is filtered at the input to a single balanced mixer to reduce the contribution of LO amplifier-generated noise to the mixer output. The resulting mixer can be reduced in size, consume less power, and have reduced noise relative to existing mixer configurations.

[0033] These circuit techniques are shown in FIGS. 7 and 8, which present block diagrams illustrating examples of a downconversion mixer 700 and an upconversion mixer 800. In particular, the filter circuits in the downconversion mixer 700 and the upconversion mixer 800 can filter intermediate frequency (IF) and RF components of the LO amplifier noise. The IF components (which may include low-frequency noise) can be shunted by an IF shunt, thereby converting the IF noise to a noiseless common-mode signal at the differential IF output of the mixer. At RF, the signal undergoes common-mode rejection to produce a differential signal. Because the LO signal is also differential, the resulting noise associated with mixing the LO differential signal with the LO amplifier noise can result in common-mode noise that again does not degrade the output noise of the differential mixer IF signal. In some embodiments, the filter circuit can include a half-wave (λ / 2) transmission line connected in parallel to the mixer LO input, which introduces very low loss while having a similar effect on the LO amplifier signal and noise at IF and RF. Note that the half-wave can correspond to the frequency of the LO differential signal.

[0034] The disclosed circuit technology differs from that used in many existing RF receiver front-ends. For example, FIG. 9 presents a block diagram illustrating a double-balanced mixer in an existing RF receiver front-end 900. In the existing RF receiver front-end 900, the RF and IF noise of the LO amplifier can be canceled by an IF summation load (transistors T3-T5, T4-T6). However, using two LO switching pairs (T3, T4 and T5, T6) can increase the noise generated by the switching pairs. Furthermore, when the input signal is single-ended, a differential signal may need to be generated (e.g., using balun B), which may introduce loss and degrade the noise figure. (Note that a balun may be a two-port component placed between a source and a load when a differentially balanced circuit is connected to a single-ended ground reference circuit.) Furthermore, the power consumption (e.g., LO power consumption) of the configuration shown in FIG. 9 may increase, and the area of ​​the existing RF receiver front-end 900 may increase (e.g., the area of ​​the LO amplifier and the additional area of ​​the balun).

[0035] Alternatively, FIG. 10 presents a block diagram illustrating an existing RF receiver front-end 1000 having a balun at the LO input. In the existing RF receiver front-end 1000, the balun may provide common-mode rejection. In particular, common-mode LO RF noise from the LO amplifier may be rejected by the balun. Furthermore, IF noise from the LO amplifier may be shunted by the balun. However, the balun may increase the area of ​​the existing RF receiver front-end 1000. Furthermore, the balun may require a more powerful LO amplifier because it is placed in series and may therefore introduce significant loss. In addition, at high frequencies, the balun may require a tailoring-matching circuit (which may include an additional capacitor), which may further increase the area of ​​the existing RF receiver front-end 1000.

[0036] In the disclosed circuit technology, a parallel common-mode filter or rejection circuit at the LO input to the mixer can be used to reject noise generated by the LO amplifier. In particular, this rejection can be performed by a half-wave transmission line connected between the two differential LO signals driven from the LO amplifier. In some embodiments, the half-wave transmission line can be implemented by a lossy, shielded microstrip transmission line on a low metal layer with traces routed within a relatively small area. Because the half-wave transmission line is connected in parallel with the differential LO line (which may have a relatively low input impedance compared to the differential impedance of the half-wave transmission line, and may have a very high impedance) at the mixer input, the insertion loss can be very small and have little or no effect on the power driven by the LO amplifier to the mixer. This configuration can be used in additional circuitry to reject common mode, for example, replacing a large transformer that may leak electromagnetic waves with a transmission-line-based circuit and half-wave transmission line to reject common mode.

[0037] Next, we will discuss filter circuits such as half-wave transmission lines. Figure 11 presents a block diagram illustrating an example of a half-wave transmission line. For common-mode signals, there may be no or zero current flowing through the half-wave transmission line at the axis of symmetry. In particular, the quarter-wave length of the transmission line may convert an open circuit into a short circuit that shorts out the common-mode signal. As a result, the common-mode signal may be suppressed by the short circuit (assuming a non-ideal short circuit). At IF (e.g., low frequencies), differential and common-mode noise may be shorted by the half-wave transmission line, which may act as a short circuit.

[0038] Figure 12 presents a block diagram illustrating an example of a half-wave transmission line. For differential mode signals, there may be a virtual ground at the axis of symmetry of the half-wave transmission line. In particular, the quarter-wave length of the transmission line may convert a short circuit to an open circuit. The differential mode signal may not be affected by the half-wave transmission line, which has very small insertion loss (which may be caused by non-ideal behavior). At IF (such as low frequencies), differential and common mode noise may be shorted by the half-wave transmission line and may act as a short circuit.

[0039] FIG. 13 presents a block diagram illustrating an example of an RF receiver front end. In FIG. 13, the LO generated IF noise contribution is s ), RF noise from the input stage (rf n ), LO amplifier noise at RF differential (LO ampn_rf_diff ), LO amplifier noise in RF common mode (LO ampn_rf_cm ), IF differential LO amplifier noise (LO ampn_if_diff ), IF common mode LO amplifier noise (LO ampn_if_cm ), LO switching pair noise at RF (LO swpairn_rf ), LO switching pair noise at IF (LO swpairn_if ) and the large signal may include a small signal including an LO signal (LO s ), which may be desirable if it is the output signal. By these definitions, the noise contribution may include:

number

[0040] In some embodiments, the LO signal may be a differential signal, the output from the mixer may be a differential signal, and the noise input may be a common-mode signal. The product of a common-mode signal and a differential signal may be a differential signal, while the product of two differential signals may be a common-mode signal. As a result, differential noise may be rejected. The half-wave transmission line may behave as an open circuit to the differential signal (because there is a virtual ground in the middle of the half-wave transmission line) and therefore may have no effect. However, for common-mode signals, there may be no current or zero current in the middle of the half-wave transmission line (because they are at the same voltage or are open in the middle). Furthermore, another quarter-wave length of the transmission line may be a short circuit, and therefore no common-mode signal is injected into the mixer.

[0041] Note that integrated circuit implementations of these circuit techniques can be very compact. Additionally, shielded, low-metal transmission lines can allow for circuitry to be placed underneath the filter circuitry. Furthermore, the use of wound transmission lines can result in very small footprint structures. For example, wound transmission lines may be defined in an area having a width of 60 μm.

[0042] The common-mode rejection of a half-wave transmission line is shown in Figure 14, which presents a block diagram illustrating an example of S-parameter insertion loss (S21) as a function of frequency for an RF receiver front end. At RF, the common mode can be suppressed by 16 dB. However, at lower frequencies, the differential mode can be suppressed by 15 dB. Note that the insertion loss of the RF signal can be less than 0.3 dB.

[0043] Furthermore, Figure 15 presents a block diagram illustrating an example of noise figure as a function of frequency for an RF receiver front end with and without a half-wavelength transmission line. Note that the noise figure improvement at low IF can be 6.5 dB, and the noise figure improvement at high IF can be 5 dB.

[0044] Furthermore, these circuit techniques may enable the use of compact, single-balanced-mixer-preceded RF front-end receivers. Using a compact, single-balanced-mixer-preceded configuration may enable the use of MIMO radar. Furthermore, by adding separately controlled phase modulation for all RF receiver inputs, a single IF chain may be used to support low-cost, high-performance multiple-input receivers.

[0045] Method embodiments will now be described. FIG. 16 presents a flow chart illustrating one example of a method 1600 for selective filtering, which may be performed by an integrated circuit. During operation, the integrated circuit may use a mixer to convert a signal between a frequency band at RF and a second frequency band that is based at least in part on a second signal, the second frequency band being smaller than the first frequency band (OPERATION 1610). Additionally, the integrated circuit may use a filter circuit in parallel with an input port to the mixer to filter the second signal (OPERATION 1612), where the filtering filters out common-mode signals above a threshold frequency and differential signals below a threshold frequency.

[0046] For example, the filter circuit may include a transmission line, such as a half-wave transmission line. Note that the mixer may convert a differential signal to a common-mode signal below a threshold frequency and convert a common-mode signal to a differential signal above the threshold frequency. In some embodiments, the threshold frequency may be between 100 MHz and 1 GHz. As a result, the filter circuit may be a short circuit for a 40 MHz common-mode signal but an open circuit for an 80 GHz differential signal.

[0047] There may be additional or fewer operations in some embodiments of method 1600. Additionally, the order of the operations may be changed and / or two or more operations may be combined into a single operation.

[0048] The disclosed integrated circuits and circuit techniques can be (or can be included in) any electronic device or system. For example, the electronic device can include a mobile phone or smartphone, a tablet computer, a laptop computer, a notebook computer, a personal or desktop computer, a netbook computer, a media player device, an e-book device, a MiFi® device, a smart watch, a wearable computing device, a portable computing device, a consumer electronic device, an access point, a router, a switch, communications equipment, test equipment, a vehicle, a watercraft, an aircraft, an automobile, a truck, a bus, a motorcycle, manufacturing equipment, agricultural equipment, construction equipment, or another type of electronic device.

[0049] Although particular components are used to describe embodiments of an integrated circuit and / or an integrated circuit containing an integrated circuit, in alternative embodiments, different components and / or subsystems may be present within the integrated circuit and / or the integrated circuit containing an integrated circuit. Thus, embodiments of an integrated circuit and / or an integrated circuit containing an integrated circuit may include fewer components, additional components, or different components, two or more components may be combined into a single component, a single component may be separated into two or more components, one or more positions of one or more components may be changed, and / or there may be different types of components.

[0050] Furthermore, the circuits and components in embodiments of integrated circuits and / or integrated circuits comprising integrated circuits may be implemented using any combination of analog and / or digital circuits, including bipolar, PMOS, and / or NMOS gates or transistors. Furthermore, signals in these embodiments may include digital signals having more or less discrete values ​​and / or analog signals having continuous values. Additionally, components and circuits may be single-ended or differential, and power supplies may be unipolar or bipolar. It should be noted that electrical couplings or connections in the previously described embodiments may be direct or indirect. In the previously described embodiments, a single line corresponding to a route may refer to one or more single lines or routes.

[0051] As previously mentioned, at least an integrated circuit may implement some or all of the functionality of the circuit technology. The integrated circuit may include hardware and / or software mechanisms used to implement the functionality associated with the circuit technology. However, in other embodiments, the disclosed circuit technology may be implemented, at least in part, using discrete components.

[0052] In some embodiments, the output of a process for designing an integrated circuit, or a portion of an integrated circuit, including one or more of the circuits described herein may be a computer-readable medium, such as, for example, a magnetic tape or an optical or magnetic disk. The computer-readable medium may be encoded with data structures or other information describing a circuit that may be physically instantiated in the integrated circuit or as part of the integrated circuit. Although various formats may be used for such encoding, these data structures are commonly described in Caltech Intermediate Format (CIF), Calma GDS II Stream Format (GDSII), Electronic Design Interchange Format (EDIF), Open Access (OA), or Open Artwork System Interchange Standard (OASIS). One skilled in the art of integrated circuit design can develop such a data structure from a wiring diagram and corresponding description of the type detailed above and encode the data structure on a computer-readable medium. One skilled in the art of integrated circuit fabrication can use such encoded data to fabricate an integrated circuit including one or more of the circuits described herein.

[0053] Although some of the operations in the previously described embodiments have been implemented in hardware or software, in general, the operations in the previously described embodiments may be implemented in a wide variety of configurations and architectures. Thus, some or all of the operations in the previously described embodiments may be performed in hardware, software, or both. For example, at least some of the operations in the circuitry may be implemented using program instructions executed by a processor or in firmware within an integrated circuit.

[0054] Furthermore, although example values ​​are provided in the foregoing description, other embodiments may use different values, and as a result, the values ​​provided are not intended to be limiting.

[0055] In the preceding description, reference is made to "some embodiments." Note that "some embodiments" describes a subset of all possible embodiments, but does not always specify the same subset of embodiments.

[0056] The preceding description is intended to enable any person skilled in the art to make and use the present disclosure, and is provided in the context of a particular application and its requirements. Moreover, the foregoing descriptions of embodiments of the present disclosure have been presented for purposes of illustration and description only. They are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Accordingly, many modifications and variations will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit or scope of the present disclosure. Additionally, the description of the embodiments set forth above is not intended to limit the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein. [Explanation of symbols]

[0057] 110 vehicles 112 Antenna 114 Antenna 116 Antenna 118 Antenna 120 Antenna 122 Antenna 205 Radar Array Controller 210 Electronic Control Unit (ECU) 212 Sensors 214 Radar Array Controller 216 Turn signal actuator 218 Steering Actuator 220 Braking Actuator 222 Throttle Actuator 224 Interactive User Interface 310 Radar System 312 Transmitting Antenna 314 Reflector or Target 316 Transmitted Signal 318 Received Signal 320 receiving antenna 410 Radar Transceiver Circuit 412 Carrier Signal (Chirp) Generator 414 Phase shifter 416 Amplifier 418 Low Noise Amplifier (LNA) 420 Mixer 422 Broadband (BB) filter 424 Analog-to-Digital Converter (ADC) 426 processor 700 Down Conversion Mixer 800 Up-Conversion Mixer 900 RF Receiver Front End 1000 RF Receiver Front End 1600 methods 1610 operation

Claims

1. 1. An integrated circuit including a radio frequency (RF) receiver, the RF receiver comprising: a mixer configured to convert a signal between a frequency band in radio frequencies and a second frequency band based at least in part on a second signal, the second frequency band being smaller than the frequency band; the mixer comprises an input port configured to receive the second signal, and a filter circuit electrically coupled in parallel with the input port; The integrated circuit, wherein the filter circuit is configured to filter out common mode signals above a threshold frequency and to filter out differential signals below the threshold frequency.

2. The integrated circuit of claim 1 , wherein the filter circuit comprises a transmission line.

3. The integrated circuit of claim 2 , wherein the transmission line comprises a half-wave transmission line.

4. The integrated circuit of claim 2 , wherein the transmission line comprises a shielded microstrip transmission line.

5. 10. The integrated circuit of claim 1, wherein the mixer comprises a downconversion mixer configured to convert the signal from the frequency band to the second frequency band.

6. 10. The integrated circuit of claim 1, wherein the mixer comprises an up-conversion mixer configured to convert the signal from the second frequency band to the frequency band.

7. The integrated circuit of claim 1 , wherein the RF receiver includes an amplifier configured to provide the second signal to the mixer.

8. 10. The integrated circuit of claim 1, wherein the signals in the frequency band include single-ended signals and the signals in the second frequency band include differential signals.

9. 2. The integrated circuit of claim 1, wherein the mixer is configured to convert the differential signal to the common-mode signal below the threshold frequency and to convert the common-mode signal to the differential signal above the threshold frequency.

10. The integrated circuit of claim 1 , wherein the second frequency band is greater than DC.

11. The integrated circuit of claim 1 , wherein the mixer comprises a balanced mixer.

12. 1. An electronic device comprising:

1. An integrated circuit, the integrated circuit including a radio frequency (RF) receiver, the RF receiver comprising: a mixer configured to convert a signal between a frequency band in radio frequencies and a second frequency band based at least in part on a second signal, the second frequency band being smaller than the frequency band; the mixer comprises an input port configured to receive the second signal, and a filter circuit electrically coupled in parallel with the input port; the filter circuit is configured to filter out common mode signals above a threshold frequency and to filter out differential signals below a threshold frequency. an integrated circuit, An electronic device comprising:

13. The electronic device of claim 12 , wherein the filter circuit comprises a half-wave transmission line.

14. 13. The electronic device of claim 12, wherein the mixer comprises a downconversion mixer configured to convert the signal from the frequency band to the second frequency band.

15. 13. The electronic device of claim 12, wherein the mixer comprises an up-conversion mixer configured to convert the signal from the second frequency band to the frequency band.

16. 13. The electronic device of claim 12, wherein the RF receiver includes an amplifier configured to provide the second signal to the mixer.

17. 13. The electronic device of claim 12, wherein the signals in the frequency band comprise single-ended signals and the signals in the second frequency band comprise differential signals.

18. 13. The electronic device of claim 12, wherein the mixer is configured to convert the differential signal to the common mode signal below the threshold frequency and to convert the common mode signal to the differential signal above the threshold frequency.

19. 1. A method for selective filtering, comprising: Radio frequency (RF) receivers using a mixer to convert a signal between a frequency band in radio frequencies and a second frequency band based at least in part on a second signal, the second frequency band being smaller than the frequency band; filtering the second signal using a filter circuit in parallel with an input port to the mixer, the filtering step filtering out common mode signals above a threshold frequency and filtering out differential signals below the threshold frequency; A method comprising:

20. 20. The method of claim 19, wherein the filter circuit comprises a half-wave transmission line.

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