Ultra-wideband stepped frequency radio frequency front end with high-order harmonic suppression

Abstract

The application discloses a kind of ultra-wideband step frequency radio frequency front ends with high-order harmonic suppression, comprising: transmitter and receiver, high-frequency local oscillator passes through driver amplifier and band-pass filter, into power divider, one-way output signal as the intermediate frequency signal of down-conversion mixer, with step frequency signal is mixed, through low-pass filter to take lower sideband signal, then through power amplifier to transmitting antenna;In receiver, the signal of receiving antenna sequentially passes through low-noise amplifier and band-pass filter, into mixer, with coupled step frequency signal is mixed, take the upper sideband signal in output signal, after driver amplifier and band-pass filter, with the other way signal of power divider output IQ mixing is carried out, and AD sampling is carried out to I channel and Q channel respectively.According to the application, without switch filter group, the effective suppression of the high-order harmonic of transmitting signal can be realized, while reducing the complexity of system, the cost is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of radar applications, and in particular to an ultra-wideband stepped-frequency radio frequency front end with high-order harmonic suppression. Background Art

[0002] With the advancement of information technology, RF front-end systems are constantly evolving. Their primary function is to transmit and receive RF signals. Stepped-frequency RF front-ends, due to their unique advantages, play a crucial role in modern radar research and applications. Their research is significant because they offer high sensitivity and dynamic range, which are crucial for accurate target detection and identification. This research not only advances radar technology but also provides more powerful and reliable detection tools for various military, industrial, and civilian applications. However, existing stepped-frequency RF front-ends, due to the nonlinear characteristics of the RF synthesis source and mixer, generate a series of high-order harmonics, impacting system performance. Summary of the Invention

[0003] In response to the shortcomings of the prior art, the present invention aims to provide an ultra-wideband stepped-frequency RF front-end with high-order harmonic suppression. By mixing a stepped-frequency local oscillator with a high-intermediate frequency (HIF), an ultra-wideband signal of a difference frequency is obtained. No harmonic components exist within the stepped-frequency range of the local oscillator, and out-of-band harmonics and spurious signals can be effectively filtered out by a bandpass filter. That is, effective suppression of high-order harmonics of the transmitted signal can be achieved without switching filter groups, thereby reducing system complexity and effectively lowering costs. In order to achieve the above-mentioned purpose and other advantages of the present invention, an ultra-wideband stepped-frequency RF front-end with high-order harmonic suppression is provided, comprising:

[0004] A transmitter comprising a high-frequency local oscillator, a first driver amplifier connected to the high-frequency local oscillator signal, a first bandpass filter connected to the first driver amplifier signal, a first power splitter connected to the first bandpass filter signal, a down-conversion mixer connected to the first power splitter signal, a first low-pass filter connected to the down-conversion mixer signal, a power amplifier connected to the first low-pass filter signal, and a transmitting antenna connected to the power amplifier signal;

[0005] A receiver includes a receiving antenna, a low-noise amplifier connected to the receiving antenna signal, a second low-pass filter connected to the low-noise amplifier signal, an up-conversion mixer connected to the second low-pass filter signal, a second power divider and a second driver amplifier connected to the up-conversion mixer signal, a stepped frequency local oscillator connected to the second power divider signal, a second band-pass filter connected to the second driver amplifier signal, an IQ mixer connected to the second band-pass filter signal, and an AD sampler connected to the IQ mixer signal; a first power divider is connected to the IQ mixer signal; and a second power divider is connected to the down-conversion mixer signal. In the transmitter, the high-frequency local oscillator passes through the driver amplifier and bandpass filter and enters the power divider. One of the output signals serves as the intermediate frequency signal of the down-conversion mixer, is mixed with the step-frequency signal, and the lower sideband signal is removed through the low-pass filter. It then passes through the power amplifier to the transmitting antenna. In the receiver, the signal from the receiving antenna passes through the low-noise amplifier and bandpass filter in turn, enters the up-conversion mixer, is mixed with the coupled step-frequency signal, and the upper sideband signal in the output signal is taken. After passing through the driver amplifier and bandpass filter, it is IQ mixed with the other signal output from the power divider. The I channel and Q channel are AD sampled respectively, and the sampled digital signal enters the digital signal processing module.

[0006] Compared with the prior art, the present invention has the following advantages: an ultra-wideband signal of a difference frequency is obtained by mixing a stepped frequency local oscillator with a high-intermediate frequency, no harmonic components exist within the stepped frequency range of the local oscillator, and out-of-band harmonics and spurious signals can be effectively filtered out by a bandpass filter, that is, effective suppression of high-order harmonics of the transmitted signal can be achieved without switching the filter group, thereby reducing system complexity and effectively lowering costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 Schematic diagram of the architecture of an ultra-wideband stepped-frequency RF front-end with high-order harmonic suppression according to the present invention;

[0008] Figure 2 FIG. 4 is a frequency conversion diagram of an example of an ultra-wideband stepped-frequency RF front-end with high-order harmonic suppression according to the present invention.

[0009] 100—Transmitter, 200—Receiver, 1001—High-frequency local oscillator, 1002—First driver amplifier, 1003—First band-pass filter, 1004—First power divider, 1005—Coupled signal, 1006—Pass-through signal, 1007—Down-conversion mixer, 1008—First low-pass filter, 1009—Power amplifier, 1010—Transmitting antenna, 2001—Receiving antenna, 2002—Low-noise amplifier, 2003—Second low-pass filter, 2004—Second power divider, 2005—Up-conversion mixer, 2006—Second driver amplifier, 2007—Stepped-frequency local oscillator, 2008—Second band-pass filter, 2009—IQ mixer, 2010—I channel, 2011—Q channel, 2012—AD sampling. DETAILED DESCRIPTION

[0010] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0011] Reference Figure 1 , an ultra-wideband stepped-frequency RF front-end with high-order harmonic suppression, comprising:

[0012] The transmitter 100 includes a high-frequency local oscillator 1001, a first driver amplifier 1002 connected to the high-frequency local oscillator 1001 signal, a first bandpass filter 1003 connected to the first driver amplifier 1002 signal, a first power divider 1004 connected to the first bandpass filter 1003 signal, a down-conversion mixer 1007 connected to the first power divider 1004 signal, a first low-pass filter 1008 connected to the down-conversion mixer 1007 signal, a power amplifier 1009 connected to the first low-pass filter 1008 signal, and a transmitting antenna 1010 connected to the power amplifier 1009 signal. The high-frequency local oscillator 1001 is selected according to the operating frequency of the radio frequency front end; the first driver amplifier 1002 is used to A signal of a high-frequency local oscillator 1001 is amplified; a first band-pass filter 1003 is used to filter out undesired frequency components in the output signal of the first driving amplifier 1002; a first power divider 1004 is used to divide the signal output by the first band-pass filter 1003 into a coupled signal 1005 and a direct-pass signal 1006; a down-conversion mixer 1007 is used to mix the coupled signal 1005 with a stepped frequency signal; a first low-pass filter 1008 is used to filter out undesired frequency components in the output signal of the down-conversion mixer 1007 and remove the lower sideband signal; a power amplifier 1009 is used to amplify the lower sideband signal output by the down-conversion mixer 1007; and a transmitting antenna 1010 is used to transmit the signal amplified by the power amplifier 1009.

[0013] Receiver 200, the receiver 200 includes a receiving antenna 2001, a low-noise amplifier 2002 signal-connected to the receiving antenna 2001, a second low-pass filter 2003 signal-connected to the low-noise amplifier 2002, an up-conversion mixer 2005 signal-connected to the second low-pass filter 2003, a second power divider 2004 and a second driver amplifier 2006 signal-connected to the up-conversion mixer 2005, a stepped frequency local oscillator 2007 signal-connected to the second power divider 2004, a second band-pass filter 2008 signal-connected to the second driver amplifier 2006, an IQ mixer 2009 signal-connected to the second band-pass filter 2008, and an AD sampler 2012 signal-connected to the IQ mixer 2009; receiving antenna 2001 is used to receive the signal reflected by the target; the low-noise amplifier 2002 is used to filter out undesired frequency components in the output signal of the low-noise amplifier 2002; the up-conversion mixer 2005 is used to mix the second low-pass filter 2003 with the stepped-frequency local oscillator 2007; the second driver amplifier 2006 is used to amplify the signal output by the up-conversion mixer 2005; the second bandpass filter 2008 is used to filter out undesired frequency components in the output signal of the up-conversion mixer 2005, and obtain the upper sideband signal; the IQ mixer 2009 is used to perform IQ mixing on the signal output by the second bandpass filter 2008 and the direct signal 1006; and the AD sampling 2012 is used to digitally acquire the I channel 2010 and the Q channel 2011. The sampled digital signals enter the digital signal processing module.

[0014] The first power divider 1004 is signal-connected to the IQ mixer 2009;

[0015] The second power divider 2004 is signal-connected to the down-conversion mixer 1007 .

[0016] Furthermore, the frequency of the high-frequency local oscillator 1001 is lower than that of the stepped-frequency local oscillator 2007. There is a frequency difference between the high-order harmonics generated by mixing the high-frequency local oscillator 1001 and the stepped-frequency local oscillator 2007 and the target signal, which can be suppressed by a filter.

[0017] Furthermore, the passbands of the first low-pass filter 1008 and the second low-pass filter 2003 are below the high-order harmonic frequency.

[0018] Furthermore, the IQ mixer 2009 performs AD sampling on the I channel 2010 and the Q channel 2011 respectively.

[0019] Example 1

[0020] See Figure 2 As shown, Figure 2FIG. 1 is a frequency conversion diagram of a specific embodiment of the present invention. In this embodiment, the transmitting and receiving operating frequency bands are 300 MHz to 3 GHz, and a stepped frequency method is used to achieve transmission covering the entire ultra-wideband. The following is a detailed description of a specific embodiment of the present invention:

[0021] In this specific embodiment, the high-frequency local oscillator frequency in the architecture is selected to be 7.5 GHz, and a coupler is used as a power distribution device, and the coupled signal enters the up-conversion mixer. At the same time, the 7.8-10.5 GHz is an ultra-wideband stepped frequency signal with an agile transition time of less than 1 ms. A power splitter is used as a power distribution device to generate two local oscillator signals for the mixer local oscillators of the transmitter and receiver respectively. The 7.8-10.5 GHz local oscillator signal is mixed with a 7.5 GHz intermediate frequency signal, and the lower sideband signal, namely 0.3-3 GHz, is taken as the transmission signal. This target signal has a low frequency characteristic of less than 3 GHz and an agile transition time of less than 1 ms. The receiver inputs the 0.3-3 GHz signal, which is mixed with another 7.8-10.5 GHz local oscillator signal, and the lower sideband signal, namely 7.5 GHz, is taken as the intermediate frequency signal, which is then mixed with the 7.5 GHz direct signal output by the coupler for IQ mixing to obtain a zero-IF baseband signal.

[0022] The number of devices and processing scales described herein are intended to simplify the description of the present invention, and applications, modifications, and variations of the present invention will be apparent to those skilled in the art.

[0023] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. An ultra-wideband stepped-frequency RF front end with high-order harmonic suppression, characterized in that: include: A transmitter (100), comprising a high-frequency local oscillator (1001), a first driving amplifier (1002) signal-connected to the high-frequency local oscillator (1001), a first band-pass filter (1003) signal-connected to the first driving amplifier (1002), a first power distributor (1004) signal-connected to the first band-pass filter (1003), a down-conversion mixer (1007) signal-connected to the first power distributor (1004), a first low-pass filter (1008) signal-connected to the down-conversion mixer (1007), a power amplifier (1009) signal-connected to the first low-pass filter (1008), and a transmitting antenna (1010) signal-connected to the power amplifier (1009); A receiver (200), comprising a receiving antenna (2001), a low-noise amplifier (2002) signal-connected to the receiving antenna (2001), a second low-pass filter (2003) signal-connected to the low-noise amplifier (2002), an up-conversion mixer (2005) signal-connected to the second low-pass filter (2003), a second power divider (2004) signal-connected to the up-conversion mixer (2005), a second driver amplifier (2006) signal-connected to the up-conversion mixer (2005), a stepped frequency local oscillator (2007) signal-connected to the second power divider (2004), a second band-pass filter (2008) signal-connected to the second driver amplifier (2006), an IQ mixer (2009) signal-connected to the second band-pass filter (2008), and an AD sampling unit (2012) signal-connected to the IQ mixer (2009); The first power divider (1004) is signal-connected to the IQ mixer (2009); The second power divider (2004) is signal-connected to the down-conversion mixer (1007).

2. The ultra-wideband stepped-frequency RF front-end with high-order harmonic suppression according to claim 1, wherein: The first power divider (1004) is used to divide the signal output by the first bandpass filter (1003) into a coupled signal (1005) and a direct signal (1006).

3. The ultra-wideband stepped frequency RF front end with high-order harmonic suppression according to claim 2, characterized in that: The down-conversion mixer (1007) is used to mix the coupled signal (1005) with the stepped frequency signal.

4. The ultra-wideband stepped-frequency RF front-end with high-order harmonic suppression according to claim 2, wherein: The IQ mixer (2009) is used to perform IQ mixing on the pass-through signal (1006) and the signal output by the second bandpass filter (2008).

5. The ultra-wideband stepped frequency RF front end with high-order harmonic suppression according to claim 1, wherein: The up-conversion mixer (2005) is used to mix the second low-pass filter (2003) with the stepped frequency local oscillator (2007).

6. The ultra-wideband stepped frequency RF front end with high-order harmonic suppression according to claim 1, characterized in that: The local oscillators of the up-conversion mixer (2005) and the down-conversion mixer (1007) are generated by the stepped frequency local oscillator (2007) via the second power divider (2004).

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