1. General introduction

Antenna testing & measurement is a very common need in the telecommunications industry in general and high frequency in particular. This is one of the basic tasks in antenna theory. Antenna theory cannot be completed if the antenna under test (AUT) measurement cannot be achieved as desired. Basically, when doing this work, we want to test the basic theoretical parameters of the antenna such as gain, efficiency, impedance or VSWR, bandwidth, and polarization of the antenna. New technology combined with data processing software can also draw the antenna radiation pattern characterization diagram.

2. Antenna transmission theory

The antenna’s transmission space is divided into 3 areas: reactive, near-field and far-field.

The spatial region with a distance greater than 2D2/λ radiation is called the far-field region, in which D is the maximum length of the antenna. In this region, the beam shape does not change with distance; in other words, the measured radiation pattern characterization is determined.

The spatial region limited from λ to 2D2/ λ, is called the near-field region. The radiation pattern characterization of the antenna in this spatial region changes with distance, especially the shape of the beams. However, we can determine the equivalent radiation pattern characterization as the far-field region by mathematical transformations from near to far-field.

The spatial region limited from the reflecting surface of the antenna to a distance λ (1 times the wavelength) is called the ultra-near field region. In this space, the antenna’s radiation has a negative impact on the antenna itself. Therefore, the signal in this region is very noisy, unstable, and has many different beam shapes that change with distance. In other words, it is challenging to determine the antenna radiation pattern in this case.

For example, with a 1m diameter antenna operating at 10 GHz (λ = 3cm), the near-field region will extend to about 2/.03 = 66m.

Due to the changing characteristics of the signal wave according to the area and distance of the antenna, antenna test and measurement methods are also divided into different ways. In fact, antennas are the main elements used for long-distance communications, when wired transmission is difficult to meet the requirements. Therefore, testing antennas in the far-field region is the most necessary and realistic task. However, setting up an antenna test, measurement, and evaluation system in this region is not easy. Antenna test and measurement methods are divided into two types, which are near-field and far-field. With the near-field measurement method, the measuring distance is relatively small, so usually, the system can be explicitly installed in the home, also known as a measuring chamber or anechoic chamber. Testing in far-field regions often involves vast distances, especially large-sized, high-frequency antennas such as antennas of radar stations, aircraft antennas, antennas in high-frequency receiver and transmitter systems, etc.

3. General requirements and specifications

3.1. Required equipment for antenna testing and measurement

When using plane waves to test the antenna under test (AUT), we can consider using a source (transmitting) antenna with known characteristics and radiation patterns, affecting the antenna in the way of random fields. Required equipment includes the following:

• Transmitting antenna and signal generator: This antenna has known radiation used to transmit to the AUT.
• Receiver system: this part determines how much power the AUT receives.
• A positioning system: This system rotates the AUT, combined with the transmitting (source) antenna, giving a radiation curve as a function of the rotation angle.

The source antenna must ensure good operation at the frequency to be tested. This antenna must be polarized in advance and have a bandwidth suitable for the AUT antenna measurement range. The source antenna is usually a horn antenna or a dipole antenna with a parabolic reflecting surface.

The transmitter ensures stable power generation according to calculations. The output frequency must also be accurate and adjustable (ability to select and change the frequency range) and reasonably stable (low-frequency drift).

The receiver will be responsible for receiving and determining the power level of the signal received from the AUT. This receiver can be supplemented with low noise amplifiers to measure low power levels and extend the measurement range of the system.

The positioning system is used to steer and control the direction of the AUT. The essence of this method is to calculate the radiation graph of the AUT based on the results obtained from a function of the rotation angle value (e.g., spherical coordinates). The system will rotate the AUT in different directions and angles so that the transmitting antenna (source) can broadcast directly from many directions. Usually, the AUT will be turned and scanned 360 degrees in a spherical shape.

3.2. Measurement space

After having the measuring equipment, setting up a space to perform the antenna test is necessary. In theory, a measurement system can be deployed with such devices anywhere. However, in reality, this needs to be selected and calculated in detail because the antenna measurement requires a space unaffected by any signal or noise during the measurement process. Ideally, we need to perform this measurement in a space without any unwanted signal reflections or emissions during the measurement process. However, this is currently impossible. Therefore, the current solution chosen is to build a closed space, blocking all types of electromagnetic waves from unwanted radiation sources and making it capable of eliminating electromagnetic reflections in the implementation area. measurement.

It is called the Anechoic Chamber or Electromagnetic Wave Shielding Chamber.

It is easy to see that this method is very suitable for the near-field antenna measurement method because the measuring chamber area can only be built to a specific limit; it cannot be expanded too large, and it will encounter construction problems: construction and costs. Far-field measurement chambers are also deployed but are not as common as near-field.

* Anechoic Chamber (Electromagnetic Wave Shielding Chamber)

The AUT and receiving antenna are placed apart in the near field, the AUT is placed on a mount that can rotate along the AZ/EL (azimuth/ elevation) axes. The receiving antenna is also capable of moving in the plane along the X, Y and Z axes. The relative motion between the receiving antenna and the AUT results in different scanning methods: planar, cylindrical and spherical scanning.

When to use the measuring chamber?

When the need for accurate measurement and evaluation of the antenna is necessary, building a measurement chamber requires space, equipment, materials, and appropriate budget investment when the antenna to be measured is small in size, and the measurement method used is near-field measurement. The measuring chamber is also more convenient for the operator, monitoring the measurement process, and is not much affected by the weather.

• Planar scanning:

The near-field measurement arrangement for performing flat scanning is depicted in the figure of the sampling step ∆x = ∆y = λ/2. The AUT is fixed. In transmit mode, the probe is moved to scan and sample step by step ∆x, ∆y, up – down/horizontal, on a plane (x,y) parallel to the AUT aperture plane, away from the AUT aperture. from 3λ to 10λ.

The receiving field data will be received by the probe, recorded and then transformed and the probe will be compensated to obtain the far-field emission pattern of the AUT. This is the simplest type of measurement, both in terms of positioning equipment (positioner) and processing software (processing software). The main error encountered in planar measurements is due to the scanning surface not being infinite, leading to errors in the sidelobe structure and limitations in azimuth (truncation error).

This method is often used to measure directional antennas, with G > 15 dBi, the maximum measured azimuth angle is about < ±70 degrees. Depending on the size of the measurement room, array antennas or reflector antennas can be measured.

• Cylindrical scanning:

The AUT rotates around the z-axis in ∆φ steps while the probe moves up and down parallel to the z-axis in ∆z steps, creating a scanning journey equivalent to a cylindrical surface surrounding the AUT. The distance between the probe rack and the AUT is chosen to avoid interaction between the AUT and the probe. The length of the cylinder determines the truncation error. The parameters of interest in this method are ∆z = λ/2, ∆φ = λ/2 R; where R is the radius of the cylinder.

This method is suitable for measuring antennas with wide beams (azimuth) with apertures in the range of less than 1.5m.

• Spherical scanning:

There are 2 methods of scanning:

The AUT rotates around the z-axis with steps ∆φ, the probe rotates in a circular orbit around the AUT with steps ∆θ, and the probe remains stationary at a point on the z-axis of the AUT.

The AUT rotates simultaneously around the z-axis and the θ axis in steps ∆φ and ∆θ. The scanning trajectory of the probe is equivalent to that of a sphere of radius R. The scanning angular resolution is ∆φ = ∆θ = λ/2 R rad.

** Advantages of the solution:

• Large measuring range, quick system setup, does not require much labor and time.
• Reasonable cost, simple testing.
• Easy to track, not affected by the weather.

** Disadvantages of the solution

• Request to build or select a space to be an anechoic chamber.

The measurement time is quite long, but the company has data processing solutions that have also optimized the processing and reduced the measurement time.

*** Some practical solutions for 5G antenna testing:

CATR system for 5G small antenna testing

• Internal dimensions (L x H x W): 3.13 x 1.65 x 1.1 m
• Reflector surface: 0.76 x 0.76 m
• Anechoic area: 0.5 x 0.5 m
• Frequency range: 2.4-41 GHz
• Signal blocking coefficient: >20 dB

Ideal for:

• BTS station
• IoT devices
• Antenna for mobile phones
• Antenna for laptop

Spherical Near-field Measurement System

An ideal system for measuring medium and low gain antennas up to 2.0 m (79 in) diameter and is well suited for testing mobile base station antennas.

• Dimensions (L x H x W): Optional x 2.9 x 2.7 m
• Scanning area: Full Spherical; Phi/Theta – 360°
• Maximum antenna load: 136 kg at 23 cm CG offset
• Maximum antenna size: 3.0 m
• Resolution: 0.01° Phi and Theta
• Position repeatability: 0.03° RMS
• Rotation speed: 20°/s Phi, 30°/s Theta

Ideal for:

• Mobile base station antennas

Spherical Near-field Measurement System

The ideal solution is to provide a complete 3D characterization of any antenna or wireless device.

• Dimensions (L x H x W): 3.7 x 4.1 x 3.7 m
• Scanning area: 360° Phi and 330° in Theta°
• Maximum antenna load: 136 kg
• Maximum antenna size: 1.5 m
• Resolution: 0.01° Phi and Theta
• Position repeatability: 0.03° RMS
• Rotation speed: 40°/s Phi, 10°/s Theta

Ideal for:

• IoT devices
• Mobile phone antenna
• Laptop antenna

*Outdoor measuring site:

When implementing the outdoor measurement plan, the AUT antenna is installed on a test positioner placed on the top of the tower (or roof, pedestal outside the system equipment control room). The end of the receiver line (the internal oscillator) is usually located below the positioner, with the mixer connected directly to the port of the AUT. The system only requires a single high-frequency path to the positioner, simplifying system setup and operation. The system can be equipped with additional outdoor screens to protect the internal oscillator from weather and extreme temperatures. Multi-port antennas can perform simultaneous measurements using a multiplexer installed before the mixer. The receiver and transmitter positions are controlled through the receiver interface.

The transmitting antenna (source) is placed opposite the receiving tower, ensuring the receiving side receives the signal. The signal source is placed near the transmitting antenna to reduce signal loss. Control communication between the transmitter and receiver sides is performed by fiber optic cable or Ethernet.

When to build an outdoor measuring site?

Outdoor measuring sites require a more complex and long-term deployment process. Of course, the efficiency of the measurement is also greatly improved, especially the practicality of the measurement, because the outdoor measurement system can measure many types of AUT antennas in different measurement ranges and sizes, huge antennas such as radar antennas, phased array antennas… In addition, outdoor measurement sites also provide more realistic results due to the influence of environmental factors during the measurement process.

Typical parameters:

• Frequency range: full frequency range supported by high-frequency devices
• Control system: stepper motor or servo motor
• Maximum antenna load: flexible, depending on requirements
• Position resolution: 0.01°
• Rotation speed: 40°/s
• Measuring system: measuring control workstation with LCD control screen
• Motor cable: Quick-connect; 40′ (12.2m)
• High frequency cable: ~6.1m; DC-18 GHz; SMA or N connection

Deployment plan

The reference antenna (source antenna) and the AUT antenna are arranged on high towers, ensuring the following distance and height requirements:

• Distance between reference antennas and AUT: r > 2D²/λ;
• Height of hAUT towers = hAS > 4D (where D is the vertical dimension of the AUT) to ensure reflections are minimized.
• Dimension d of reference antenna: d < 0.37 λR/D

To ensure amplitude taper at the AUT surface and reflected noise due to the environment, the first null point is required to be lower than the base of the antenna. If you want to reduce reflections further, you can use range fences.

** Advantages of the solution

• Wide measuring range, can measure many types of antennas.
• Measurements are performed quickly, and the measurement results are very close to reality.
• High professionalism and excellent reliability of results.

** Disadvantages of the solution

• Large cost and lengthy implementation time to ensure technical and project quality.
• Physically affected by weather and climate; however, there are solutions to protect the project.

4. List of investment equipment

Please get in touch with us for more detailed information about the solution.

Our company always wishes to become a reliable partner and a leading supplier of equipment and solutions for the success of our customers. For more detailed information, please contact:

MITAS Hanoi Technology JSC

Address: 5th Floor, C’Land Building, No. 81 Le Duc Tho St., My Dinh 2 Ward, Nam Tu Liem Dist., Hanoi, Vietnam           

Web: https://mitas.vn  | Tel: (+84) 243 8585 111 | Email: sales@mitas.vn

The trust and support of our customers are a driving force and an invaluable asset to our company. We sincerely thank you./.

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Radar Cross-section (RCS) is a measurement of a target’s ability to reflect the radar signal in the direction of the receiving radar, which is a measurement of the ratio of the backscatter quantity per cubic angle unit in the direction of the radar target on the power density blocked by the target. RCS measurement aims to ensure that the designs of commercial companies in this field, military helicopters, and radar systems also achieve the desired quality and performance.

The accuracy of RCS measurement directly affects an aeronautical system’s safety and successful operation. In the military, stealth technology is used to reduce RCS and make it difficult to detect targets. In commercial aviation, a large RCS value is essential, from which the aviation radar system can easily detect, locate, and land safely. In practice, tactical jets typically have RCSs between 5 and 100 m2, and bombers typically have RCSs between 10 and 1000 m2. In contrast, stealth aircraft have RCS below 0.1 m2; some advanced designs can go down to 0.0002 m2.

The vector network analyzer (VNA) is the device of choice in RCS measurement applications because of its speed and accuracy in setting and measuring the S parameter. The enhanced VNA series enables the required performance allocation and features such as gating time domain measurement to simplify RCS measurement in the aircraft or on-site.

Radar range equation

The radar system (Figure 2) transmits a signal pulse through a transmitting antenna with a gain of Gt. The signal amplitude at the output of the transmitting antenna is attenuated by free-space transmission. At the target, some of the power (backscatter) is reflected toward the radar. The ratio of the backscattered power to the incident power is the RCS of the target. Loss amplitude is due to free space. Therefore, the signal received by the receiving antenna has a gain Gr and is detected in the receiver.

The block diagram (Figure 2) describes the physical blocks of the radar. The equivalent circuit of the radar is shown in Figure 3. The transmitting and receiving antenna gains are characterized by the amplifiers, then the target.

Capacitors are characteristic of free space loss. The VNA system used to measure the S21 has the same schematic diagram as the radar system. It performs the response in the S21 frequency domain of the system when port 1 of VNA is connected to the transmitting antenna and port 2 is connected to the receiving antenna.

Although VNA is very popular for frequency domain measurement applications, the addition of time domain and Gating Time analysis features makes it possible to simulate radar pulse performance by eliminating reflection gaps that do not affect the target. A 12-month period of VNA’s error correction is to minimize system failures due to loss of coordination or leakage and to set the reference plane correctly.

Polarization

The polarization of the reflected signal’s electric field vector may differ from the polarization of the transmitted signal. The shape of the target affects the depolarization factor.

To perform precise depolarization, image the fully polarized matrix into the independent electric field’s horizontal and vertical field components. This leads to the requirement of two polarized transmitters and receivers. From the measurement, a polarization matrix will be generated to describe the polarization effect, thereby accurately performing depolarization.

VNA measurement

Figure 4 shows the measurement of the S parameter in the frequency domain. The frequency range of the measurement reflects the radar’s band (8.2 to 12.4 GHz, with an X-band WR-90 waveguide). VNA’s time domain feature transforms the frequency domain S parameter measurement into the time domain.

The basis of the transformation is Alias Free Range (AFR). The transformation is a circular function and iterates itself periodically out of its own time range, t=1/(frequency step magnitude). The frequency step magnitude is proportional to the sweep range and inversely proportional to the number of sweep points.

For example,

At band X, the scan range is 4GHz; there are 4001 scan points, AFR = 4000/4.0GHz= 1000 ns corresponding to 300 m of allowable deviation range. Within 300m of the 2-way distance, the target should be placed within 150m from VNA.

A typical helicopter RCS measurement configuration using VNA is shown in Figure 5. A transmitting antenna (connecting VNA port 1) and receiving antenna (connecting VNA port 2) are placed on the same plane. The measurement target consists of a helicopter placed on the flight path or over an area with few reflective objects.

Implementing S21 measurements (frequency domain) for VNA is done similarly to radar when configured. The coax output is connected to the waveguide-coaxial converter. Port 2 connects to the output of the waveguide receiver antenna.

Both antennas are connected as close as possible on the same horizontal or vertical plane. To construct the polarization matrix, both transmitting antennas must be able to rotate 90 degrees. The target must be located within a range less than AFR/2 but far away enough to ensure that the entire target is within the antenna’s beam.

RCS measurement

A 12-month calibration feature is implemented at the coax output to build a standard reference plane for RCS travel. The frequency domain S21(f) measurement is performed on the target range. The S parameter data is transformed over the distance domain S21(d) by performing a bandpass process. The system can be calibrated in RCS by measuring the known target in advance of the RCS and referencing all other targets to the known target.

The S21(f) measurement is taken as a standard measurement. The data of the S21 measurement is transformed in the time domain mode, and a suitable gate timing is set at the standard range. The amplitude S21(std) of the standard reflectance is calculated.

The value of the measurement reflects the RCS measurement. If the standard target is a sphere with an RCS of 1m2, then the RCS of the target is given by the equation:

The data unit is dBsm. Conversion formula: dBsm=10Log(RCSm2) (dB)

Our company always wishes to become a reliable partner and a leading supplier of equipment and solutions for the success of our customers. For more detailed information, please contact:

MITAS Hanoi Technology JSC

Address: 5th Floor, C’Land Building, No. 81 Le Duc Tho St., My Dinh 2 Ward, Nam Tu Liem Dist., Hanoi, Vietnam           

Web: https://mitas.vn  | Tel: (+84) 243 8585 111 | Email: sales@mitas.vn

The trust and support of our customers are a driving force and an invaluable asset to our company. We sincerely thank you./.

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With continuously increasing data rates, the signal integrity aspects of high-speed digital designs and the components used are becoming increasingly complex. Especially at higher data rates, vector network analyzers (VNA) are gradually replacing traditional time domain reflectometry (TDR) setups for examining passive elements, such as connectors, cables, PCB, etc. The applications and conveniences of using VNA make VNA the chosen device in the field.

Purpose:

When performing tasks such as verifying high-speed signal structures on a PCB, measurements must be implemented on specific layers without the impact of probes, converters, etc. It requires using precise de-embedding algorithms to calculate and remove these effects from the measurements, leaving only the results for the region of interest.

Measurement solution:

The setup below shows an example to verify high-speed differential signals on PCB up to 20 GHz.

The device used is a 4-port VNA vector network analyzer. Common de-embedding tools such as (Delta-L, EMStar Delta-L+, EMStar Smart Fixture De-embedding (SFD), or AtaiTec In-Situ De-embedding (ISD) can be run directly on the machine, without the need for an additional external one.

Automated Implementation Process

To simplify this process and guide the operator through the test steps, testing is often automated through software. The screenshot on the left shows an example of the three stages of this test procedure:

• Measure the two short-circuit terminals to calculate the error (de-embedding).
• Measure the entire circuit to be tested.
• Calculate the results of the area to be measured based on the de-embedding method.

Eye Diagram

To meet some advanced needs, the network analyzer can be used to analyze the lattice plot of the test data area. This feature allows users to evaluate signal quality, such as amplitude noise, time-domain chaos, etc. In addition, it can also set up a mask test to quickly assess PASS/FAIL results.

Our company always wishes to become a reliable partner and a leading supplier of equipment and solutions for the success of our customers. For more detailed information, please contact:

MITAS Hanoi Technology JSC

Address: 5^th Floor, C’Land Building, No. 81 Le Duc Tho St., My Dinh 2 Ward, Nam Tu Liem Dist., Hanoi, Vietnam          

Web: https://mitas.vn  | Tel: (+84) 243 8585 111 | Email: sales@mitas.vn

The trust and support of our customers are a driving force and an invaluable asset to our company. We sincerely thank you./.

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1. Basics of analog signal analysis (ASA)

The Huntron Tracker outputs an AC sine wave signal with the correct limiting electric current to a component and displays the resulting electric current, voltage drop, and any phase shift on the device display. The current causes the vertical axis signal line deviation on the screen, while the voltage along the component causes the horizontal axis display signal deviation. The signal line that displays the results on the screen is called the analog display signal.

Understanding the ASA core circuit is the key to understanding how the analog display signal responds to the difference of component types. The ASA is sometimes referred to as a “V/I test” and since the constitutive current is a function of the impedance of the circuit, the displayed analog signal can be simulated by Ohm’s law.

V= IR (with V: voltage, I: current, and R: impedance)

The following figure shows a schematic diagram of the ASA core circuit. The sine wave signal source is the test signal source and is connected to an impedance voltage divider composed of Rs and RL. Resistive load, RL, is the impedance of the test device. RL is connected in series with an internal impedance source Rs; because Rs is fixed, both the voltage along the device being measured and the current through it are the sole function of RL.

Each test signal or range has three parameters: source voltage Vs, impedance Rs, and source frequency Fs. When using the ASA for error checking, the measuring object is selected for a range so that the display shows enough signal line information. The Huntron’s device can adjust the signal for easy reading and analysis by varying the parameter ranges. The source voltage Vs of the test signal can be used to increase or bypass the semiconductor switching and semiconductor cascade characteristics. Fs, or the frequency of the test signal source, can be used to increase or ignore the response coefficient (inductance and capacitance) of a component or a circuit node. Rs or source impedance is used to match the load impedance to be measured and provides a wealth of insight into the displayed signal curve.

2. Signal form of four basic types of components

Including Resistance, Inductance, Capacitance, Semi Conductance with the following shape:

3. Huntron’s Error-Assessment Solution

Huntron’s solution allows to compare the signal form of two components of the same type with each other or components in the same position on two identical boards to easily detect which component is damaged and replace it.

In the figures shown below, the red signal line represents the signal of the faulty component, and the blue signal line shows the component operating normally.

With this reference method, Huntron’s solution can easily and intuitively detect and replace damaged elements in the circuit board, thereby providing a rapid repair process.

In addition to manual measuring equipment, Huntron also offers automated measuring systems for industrial-scale mass inspection. By storing the location and value of each component on the circuit board in normal operation as a comparison sample, for the following circuit tests of the same type, the device can automatically check and compare the value of each measured component with standard values to find fault locations many times faster than conventional circuit detection.

Our company always wishes to become a reliable partner and a leading supplier of equipment and solutions for the success of our customers. For more detailed information, please contact:

MITAS Hanoi Technology JSC

Address: 5^th Floor, C’Land Building, No. 81 Le Duc Tho St., My Dinh 2 Ward, Nam Tu Liem Dist., Hanoi, Vietnam          

Web: https://mitas.vn  | Tel: (+84) 243 8585 111 | Email: sales@mitas.vn

The trust and support of our customers are a driving force and an invaluable asset to our company. We sincerely thank you./.

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Cables and adapters are often left unnoticed by users in RF/microwave circuits and systems until they fail to perform as expected. Cables and adapters have quite simple functions in a system as they help transmit signals from one point to another. The better they are, the less they change signal characteristics such as amplitude, frequency, and phase and provide highly reliable connections to the rest of the system. However, the signal and applications are very wide, with a various range of high and low frequencies. Therefore, it is required to choose suitable cables, connectors, and connectors for the deployed application.

Choosing a cable is simply deciding to use between rigid and bendable cables or between semi-rigid and flexible coax. Semi-rigid coaxial cable has been used in RF/microwave systems for decades, with electrical efficiency advantages. As the name suggests, semi-rigid cables limit flexibility and maneuverability and often have to be cut and/or assembled with connectors to achieve the correct length in accordance with the mechanical requirements of the system. Although cable flexibility is limited, this type of coax cable typically has less insertion loss than flexible cables with similar diameter and size.

As a compromise between these two cables, manually crimped cables provide additional flexibility and can be bent to the required shape without any required tools. This cable type also achieves significantly improved insertion loss compared to flexible cables, but not as low as semi-rigid cables.

High-frequency cable is available from many different manufacturers with impedance characteristics of 50Ω and 75Ω, the latter commonly used in CATV cable television systems. Cable loss is usually defined as the loss per 100 feet of cable at a given frequency, and this parameter is essential when comparing cables to each other. All cables have an electrical length specification, which is the number of wavelengths per unit length of the cable at a given frequency.

The electrical length of a cable can also be considered as a phase delay, or the time it takes for a signal to travel from one end of the cable to the other compared to the time it takes for the signal to travel through the equivalent distance. According to the phase delay or propagation delay, the electrical length will often be defined as nanoseconds. The dielectric constant of the insulating material between the inner conductor and the outer sheath has a significant influence on the propagation delay, as it affects the signal propagation along the cable. To achieve low signal delay, insulating materials with a low dielectric constant are often used between the inner conductor and the outer conductor layer of high-frequency coaxial cables.

Several commercial suppliers of coax cables provide helpful application information in selecting cables and information on the performance effects of different cabling materials. One of the many important notes, such as “Solid Core and Braided Cables”, emphasizes the difference between a coaxial cable with a solid core and two types of braided cable (one with 7 fibers and one with 19). All three cables have SMA connectors and the test frequency ranges from DC to 18 GHz.

In manufacturing cables, it is necessary to maintain a consistent impedance level. To do this, with a cable with a solid core, it is essential to minimize the change in cable diameter both inside the core and outside the cable. For braided cored cables, the stranded cores must be organized to ensure small size tolerances to maintain the cable’s impedance. This is the difficulty in making stranded core cables that makes the production process of stranded core cables more expensive than solid core cables. However, braided core cable has the advantage of durability and flexibility.

From measurements at the same frequency, solid core cable has the lowest attenuation, followed by braided cable with 7 fibers and finally braided cable with 19 fibers (the most significant reduction). For each type of cable, signal attenuation also rises with increasing temperature. The solid core cable gives the best amplitude stability when bending, followed by braided cable with 19 strands, and finally, braided cable with 7 fibers (the worst amplitude stability in bending).

In terms of phase stability when bending, braided cables give the best results; 7-strand braided cables are least affected by phase changes when bent, followed by 19-strand braided cables and cored cables, especially susceptible to phase change when bending. In summary, in an application (e.g., in a test system), if a lot of bending is required, braided cables will be a better choice than solid cables, which tend to attenuate after 10000 inflection points.

Our company always wishes to become a reliable partner and a leading supplier of equipment and solutions for the success of our customers. For more detailed information, please contact:

MITAS Hanoi Technology JSC

Address: 5^th Floor, C’Land Building, No. 81 Le Duc Tho St., My Dinh 2 Ward, Nam Tu Liem Dist., Hanoi, Vietnam           

Web: https://mitas.vn  | Tel: (+84) 243 8585 111 | Email: sales@mitas.vn

The trust and support of our customers are a driving force and an invaluable asset to our company. We sincerely thank you./.

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