Solar Cable,Pv Cable,Pv Solar Cable,Dc Solar Cable HENAN QIFAN ELECTRIC CO., LTD. , https://www.hnqifancable.com
Millimeter wave measurement technology challenges and benefits
The most promising millimeter-wave applications today are primarily found in the E and V bands. The E-band spans from 60 GHz to 90 GHz, where only line-of-sight (LOS) transmission is viable due to significant atmospheric absorption. Gases like oxygen, water vapor, and nitrogen absorb energy at specific frequencies within this range. Despite these challenges, the availability of ample spectrum resources continues to drive industry interest in exploring future technologies for these bands. Similarly, the V-band, ranging from 40 GHz to 75 GHz, is widely used in satellite communications.
Three key applications are currently being developed in these frequency ranges: mobile backhaul, automotive radar, and Wi-Gig (Wireless Gigabit). Mobile backhaul is crucial as hyper-heterogeneous networks rely on numerous small base stations, increasing the demand for high-capacity return links. These wireless millimeter-wave connections, with bandwidths exceeding 1 GHz, provide a fiber-like solution for modern and future network needs. Automotive radar, particularly operating at 79 GHz, uses FMCW technology to achieve high accuracy in detecting objects in motion. Wi-Gig, a new WLAN standard, enables ultra-high-speed data transfer, such as uncompressed HDTV and real-time media streaming, at 60 GHz using a 2 GHz bandwidth.
Given the unique characteristics of millimeter-wave signals, specialized measuring instruments are essential to ensure the successful implementation of these technologies. These instruments must offer excellent dynamic range to handle highly attenuated signals and the capability to measure ultra-wideband signals effectively.
**Challenges of Millimeter-Wave Devices and Measurement Schemes**
**2.1 Harmonics**
Harmonic mixers operate by utilizing harmonic components of the local oscillator (LO) signal during the mixing process. While they offer a cost-effective and simple solution, they come with limitations. As frequency increases, multiple harmonics introduce losses that degrade the dynamic range. Additionally, image response becomes a critical issue because unwanted frequency components can interfere with the desired signal. For example, if a harmonic mixer designed for an IF frequency of 1.58 GHz is used to measure a 4 GHz bandwidth signal from an FMCW radar, the mirrored response could overlap with the actual signal, making it impossible to accurately measure parameters like frequency error or transmit power. Image suppression techniques may help, but they are ineffective for FMCW modulation due to its continuously changing frequency.
**2.2 Typical Downconversion Configuration**
To address image response issues in harmonic mixer-based systems, a classic downconversion setup is often used. This configuration avoids the use of harmonics in the LO signal, allowing for a more stable intermediate frequency (IF) design. A continuous wave combined with a multiplier generates the required LO signal for downconversion. However, this approach requires multiple components—such as a mixer, local oscillator, multiplier, filter, and gain amplifier—which can be complex to set up, calibrate, and maintain.
**2.3 High-Performance Base Mixers**
Anritsu’s high-performance base mixers, such as the MA2808A and MA2806A, are designed specifically for E-band and V-band applications. These integrated downconverters use waveguide technology, built-in single-stage multipliers, low-noise amplifiers, and filters to overcome many of the limitations of traditional mixers. They offer superior dynamic range, minimal image response, and simplified integration with spectrum analyzers. Compared to harmonic mixers, they provide better sensitivity and image rejection, while also offering a compact and efficient solution that reduces system complexity and maintenance costs.
**3. Typical Measurement Items for Millimeter-Wave Equipment**
Testing millimeter-wave devices typically involves two main aspects: RF output characteristics and modulation or signal characteristics. For example, under ETSI EN 302 264-1 standards, transmit power, frequency error, and stray radiation must be measured with high sensitivity. OTA testing is essential due to the susceptibility of millimeter-wave signals to reflections and absorption. At 79 GHz, a test setup must achieve a sensitivity of around -142 dBm/Hz to meet EIRP requirements. Traditional harmonic mixers often fall short due to high conversion losses, but modern solutions like the MS2840A spectrum analyzer paired with the MA2808A mixer deliver improved performance.
**3.1 Broadband Modulation Test**
Phase noise is a critical factor when evaluating millimeter-wave signals, especially for applications like FMCW automotive radar. Poor phase noise performance can make it difficult to distinguish between transmitted and received signals, leading to inaccurate measurements. The MS2840A, combined with the MA2808A mixer, provides exceptional phase noise performance, meeting stringent automotive radar requirements and ensuring accurate signal analysis.
**4. Summary**
With the rollout of 5G networks and the growth of ADAS, the demand for millimeter-wave systems is increasing rapidly. To test these advanced technologies, spectrum analyzers with external mixers must avoid image response issues, provide sufficient sensitivity for OTA testing, and have strong phase noise performance. The combination of the MS2840A spectrum analyzer and the MA2808A high-performance waveguide mixer offers an ideal solution, meeting all these requirements efficiently and reliably.