This content is the right way to enhance your knowledge and I like it this post. I want more new updates and keep posting! Record the new S21 values. I didn't catch this point. S21 represents power or voltage, how this can be used as gain change? Nice blog, I eagerly waiting for your new post. Thanks for sharing keep sharing more good blogs.

Nice Article, valuable content Contact Advertise. Gain is one of the key specifications in antenna datasheets. It is defined as the ratio of the intensity of an antenna usually in direction of peak radiation relative to an isotropic antenna. An isotropic antenna is a hypothetical antenna that radiates with equal intensity in every direction without any losses. Figure 1: A WBH horn antenna gain chart from datasheet. Too little of it will cause the signal to fade away before reaching its destination.

Too much of it will cause distortion products in your receiver. Hence, antenna gain is an important parameter in helping us to plan or design wireless transmission link budget.

how to measure antenna gain using a network analyzer

There are several ways to measure antenna gain and will be covered in several parts. This being the first part, will cover the gain-transfer method which is also known as gain-comparison method.

The AUT or antenna under test is the one which we are interested in finding out the gain. The reference antenna is the one which the gain G Ref is accurately known, has a high degree of dimensional stability and polarization purity. It is used as a benchmark. For this purpose, we can consider several types of instrument choices:. However, for convenience and ease of use, we will take a look how to measure antenna gain using a network analyzer because a network analyzer typically comprises of both source and receiver.Remember Me?

How to measure S11 on active antenna using Network Analyzer. Re: How to measure S11 on active antenna using Network Analyzer hi there, maybe let me explaine a bit more. Normally when we want to measure S11 for a passive antenna, we can directly connect to the Network Analyzer. Right now this device that I have which the antenna is connected with a LNA. I am not interested on the LNA part, I just want to measure the antenna to check the performance without having disconnect the LNA from the antenna.

So how should I go around about it? Re: How to measure S11 on active antenna using Network Analyzer About all you can do is sweep the antenna with another broadband antenna from a few feet away and figure out if its resonant freuquency is correct.

Possible to elaborate more on how to do the sweeping? Which equipment to be use? Re: How to measure S11 on active antenna using Network Analyzer As biff44 mentioned, you can place a broadband antenna in front of your system and then measure the S11 of the broadband antenna. The resonant frequency should be depicted with a lower S As far as i know you have to brake the connections in order to only characterize the antenna.

It's a reasonable way to check antenna tuning and gain. The LNA gain and input impedance must be known, however. If you can't rely on the LNA or want to measure strictly antenna S11, you have to break the connection. You need to sweep the frequency while measuring S21 on the network analyzer. If one of the antennas is a known good broadband one, then the transmission hump should equal the center frequency of the antenna under test. In practice, sometimes this works, sometimes not. If your antenna under test is far off Bridging over the LNA to measure S11 might be useful.

Although as a minimum you will want to put a couple ferrite clamps on the coaxial cable where it attaches to the PCB. And where to get it? Re: How to measure S11 on active antenna using Network Analyzer If an active anatenna has been designed with a dedicated amplifier, S11 would be meaningless because the antenna can be matched to an arbitrary amplifier impedance or vice versa.

If the amplifier is a standard LNA with 50 ohm matching, S11 can be a reasonable criterion. Im my opinion, a gain measurement with a reference dipole is sufficient to check a GPS antenna quality despite of amplifier noise level. Directional characteristics of the antenna I guess, a usual patch antenna? Re: How to measure S11 on active antenna using Network Analyzer A broadband antenna can be a horn antenna.

Re: How to measure S11 on active antenna using Network Analyzer. Originally Posted by FvM. Similar Threads How to use a 2-port network analyzer to measure antenna gain How to measure S2P of the antenna using network analyzer! How to measure the VGA by the network analyzer 0. Part and Inventory Search. Welcome to EDABoard.

Design Resources. New Posts. PIC16F interface with ds RTC running 10 sec slow Dear senior assemblers.Gain is one of the key specifications in antenna datasheets. It is defined as the ratio of the intensity of an antenna usually in direction of peak radiation relative to an isotropic antenna.

An isotropic antenna is a hypothetical antenna that radiates with equal intensity in every direction without any losses.

Too little of it will cause the signal to fade away before reaching its destination. Too much of it will cause distortion products in your receiver. Hence, antenna gain is an important parameter in helping us to plan or design wireless transmission link budget.

There are several ways to measure antenna gain and will be covered in several parts. This being the first part, will cover the gain-transfer method which is also known as gain-comparison method. The AUT or antenna under test is the one which we are interested in finding out the gain. The reference antenna is the one which the gain G Ref is accurately known, has a high degree of dimensional stability and polarization purity.

It is used as a benchmark. However, for convenience and ease of use, we will take a look how to measure antenna gain using a network analyzer because a network analyzer typically comprises of both source and receiver. Record the new S21 values. You are commenting using your WordPress. You are commenting using your Google account. You are commenting using your Twitter account. You are commenting using your Facebook account.

Notify me of new comments via email. Notify me of new posts via email. Skip to content Open Menu Search. Search for: Close. September 8, Gain is one of the key specifications in antenna datasheets. Have a far-field separation between the antennas. Ensure the antennas are well aligned in terms of polarization and direction of maximum radiation intensity. Activate the S21 measurement. Set the frequency range of interest on the network analyzer.There are several test instruments and test approaches that can be used to measure VSWR, each with its advantages and disadvantages.

A variety of approaches can be used to measure VSWR using test instruments ranging from VSWR meters to directional power meters, and antenna analyzers to vector network analyzers. In some ways it is possible to consider that there are two forms of VSWR measurement dependent upon how they are implemented, the test instrument, and the way in which the measurements are made. The second type of VSWR measurement is performed by test instruments that supply a small stimulus to the antenna or load.

They detect the response and from this they are able to provide information about the antenna performance, including its VSWR.

how to measure antenna gain using a network analyzer

Types of VSWR measurement In some ways it is possible to consider that there are two forms of VSWR measurement dependent upon how they are implemented, the test instrument, and the way in which the measurements are made. Typically they are made with a transmitter operating with a reasonable level of power. The VSWR meters used are often left in line during normal operation as a monitor of current readings.

In this way they can provide a very useful indication of a fault occurring, or a rise in VSWR due to another issue during operation. These VSWR measurements and tests are normally done during set-up or development and then only as required. They cannot be left in circuit during normal operation as they cannot operate with the transmitter in situ and providing its power.

They are often available from amateur radio and CB suppliers as well as a number of other sources. Although these VSWR meters are not always particularly accurate, they can provide an excellent way of measuring VSWR easily and in a cost effective manner. There is a wide variety of VSWR meters available.

How to measuring antenna gain using return loss S11

They range from the very cheap small units aimed at CB usage through higher quality models often aimed at amateur radio operators and beyond. The basis of a VSWR meter is a directional coupler. This samples a small amount of power in one direction and then uses a diode to rectify this after which it is applied to a meter. Two couplers may be used: one for each direction, or one may be used and this can be switched.

how to measure antenna gain using a network analyzer

As directional couplers are frequency sensitive, make sure that the VSWR meter is able to operate on the frequencies that are needed. Read more about. Supplier Directory For everything from distribution to test equipment, components and more, our directory covers it. Featured articles.Knowledge of both magnitude and phase characteristics is needed for successful higher-level component integration.

Phase measurements are made using S-parameters, just like amplitude measurements. A phase measurement is a relative ratio measurement and not an absolute measurement. Phase measurements compare the phase of the signal going into a device the incident signal to the phase of the device's response signal. The response signal can be either reflected or transmitted. The following graphic shows the phase shift in time or degrees between an incident signal and a transmitted signal as might be seen on an oscilloscope display.

Measuring phase is a critical element of network analysis. The following graphic lists five reasons for measuring both magnitude and phase. When used in communications systems to pass signals, components or circuits must not cause excessive signal distortion.

This distortion can be:. Linear, where flat magnitude and linear phase shift versus frequency is not maintained over the bandwidth of interest. It is important to measure how reflective a component or circuit is, to ensure that it transmits or absorbs energy efficiently. Measuring the complex impedance of an antenna is a good example.

The analyzer's phase format displays a phase-versus-frequency or phase-versus-power measurement. Complex impedance data is information such as resistance, reactance, phase, and magnitude that can be determined from an S11 or S22 measurement.

Complex impedance data can be viewed using either the Smith Chart format or the Polar format. AM-to-PM conversion is a measure of the amount of undesired phase deviation PM that is caused by amplitude variations AM of the system. AM-to-PM conversion is usually defined as the change in output phase for a 1-dB increment in the input power to an amplifier i.

Deviation from linear phase is a measure of phase distortion caused by a device. Ideally, the phase shift through a device is a linear function of frequency. The amount of variation from this theoretical phase shift is known as its deviation from linear phase also called phase linearity. Group delay is another way to look at phase distortion caused by a device. Group delay is a measure of transit time through a device at a particular frequency. The analyzer computes group delay from the derivative of the measured phase response.

Although deviation from linear phase and group delay are similar measurements, they each have their purpose. Able to characterize devices that pass phase modulated signals, and show units of phase rather than units of seconds.

More easily interpreted indication of phase distortion than deviation from linear p hase.Objective: This experiment will introduce the student to measurement techniques using a Network Analyzer by making measurements of several antennas and comparing their results to theoretical values.

The antenna characteristics to be evaluated are a half-wave dipole, quarter-wave monopole, five-element Yagi, and a source antenna. Procedure: 1. Measure the physical dimensions and calculate the operating frequency of the half-wave dipole, quarter-wave monopole, and yagi antennas. Record your findings. Using the Network Analyzer in a single port S11 measurement mode, measure the input impedance of the three antennas.

Sweep the frequency an octave above and below the calculated operating frequency and record your results. Tip: To measure the input impedance the network analyzer setting should be as follows:.

Connect the antennas to the Network Analyzer as shown in Figure 1. Obtain all data necessary to describe the following antenna characteristics: a Directivity plot antenna pattern in appropriate plane b Polarity c Path Loss power loss from reference antenna to antenna under test AUT as a function of distance.

Microwave antenna, RF measurement, network analyzer, frequency analyzer, antenna measurement, dipole, yagi, monopole, elements, reflector, gain, S11, S21, reflection coefficient, input, output, noise figure, NF, RF system, polarization, refraction, wave, VSWR, wavelength, far field, near field, wavefront, input port, thru measurement, HP, Agilent, manufacture, component, calibration, CAL, marker, swept, dynamic range.

Microwave Amplifiers. Telecommunications II. Telecommunications III. Custom Search. Measuring Antenna Characteristics using a Network Analyzer Objective: This experiment will introduce the student to measurement techniques using a Network Analyzer by making measurements of several antennas and comparing their results to theoretical values. Tip: To measure the input impedance the network analyzer setting should be as follows: A.

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how to measure antenna gain using a network analyzer

How to use a 2-port network analyzer to measure antenna gain. Could you let me know right methods? Thank you very much in advanced! I connect the two antennas at the two ports port1 and port2 through the two identical cables, and set the frequency at f MHZ and the distance d meter between the two antennas.

How To Measure Antenna Gain (Part 1) – Gain Transfer Method

In order to get the gain of the AI connect A and B to Port2 as a receiver respectively two timesC is connected to Port1 as a transmitter. I am not sure whether the above methods are right or worng. It will be greatly appreciated if anyone knows well these methods and put more details. Thank you very much. You gave very clear explains, especailly addressing polarization! How about the first method that is used to measure the gain of the two identical antennas.

In a standard S-parameter measurement, this wave is fed to the input port port 1 of the DUT forward measurement.

In a standard S-parameter measurement, this wave is transmitted at port 2 of the DUT forward measurement. I have meeting a very stuff problem as attached.

Thank you very muchAdded after 5 minutes: I try to attach a file. These emissions would influence the radiated test. Let's me think through your messages for a while. It looks that S21 is always too much down from our setup measurement system.

So, the gain of AUT is almostly "-". What are problems that cause these wrong results? Thank you and looking forward to hearing you. For precise antenna gain measurements you need to use a bigger chamber at least 3m length.

Try the dipole substitution method that I mentioned before, and maybe get better results using your small chamber. Yes, a bigger chamble should be better, I will try to measure them in a bigger space and to see what is happening. But I am still liitle confusedfor the dimension of chamble is enough for min. Do you think that the problem is more probably due to the size of the pyramid absorber? Could you give me an approximation to elevate a right size of pyramid absorber for given frequency ranges?

Re: how to measure s21 Dear vfone, could you give me a reference where to find such a formula? A book, an article I'd need it for a citation in my thesis Many thanks. Originally Posted by vfone. Re: How to use a 2-port network analyzer to measure antenna gain There can be odd effects in such measurements.