All posts by Sheetal Rajput

Microstrip Isolators – A Crucial Electronic Device

Microstrip isolator is a radio frequency segregator which is made by applying microstrip technology in which a conductor is separated from the ground plane by a dielectric layer called the substrate. Microstrip lines are used to conduct microwave frequencies.

The isolator’s function is to guard other RF components from excessive signal reflection. Microstrip isolator can be built to cover different frequency ranges from 2.0 to 60 GHz.

Microstrip lines are one-directional transmission paths for RF. The Microstrip isolator captures the reflected power and dissipates it as heat.

The selected isolator path provides negligible insertion loss and excellent isolation for stripline based components and other module integrations. It is a crucial and critical device where port isolation or VSWR is concerned.

When determining the isolator for any purpose it is recommended that one first ascertains the following:

  1. – Frequency range of application.
  2. – The power load that the isolator would handle.
  3. – Insertion loss needed by the system, and
  4. – Port to port isolation needed.

Microstrip isolator circuits are used in high-frequency commercial, space, and military applications.

Microstrip technology-based devices are very economical as compared to wave-guide technology-based similar products and is far lighter and compact in dimension.

Microstrip has inherent limitations: low power handling capacity, higher losses, and moreover, it is not an enclosed device and hence prone to radiation.

Raditek offers many types of microstrip isolators on their website.

The Multipurpose High Power Circulator

A circulator is a 3 or 4 port non-reciprocal, Ferro-magnetic, device which transfers the power to other adjacent ports as per the circuitry design.

Circulators allow high power flow which is the microwave energy, only in one direction within the RF circuit. Such circulators can have isolation ratings ranging from 16dB to 22dB.

When one of the 3 or 4 ports is terminated-matched condition-the other ports become isolated in the reverse direction. Therefore and isolator is a circulator with matched terminations.

Circulator high power is made out of ferrite material that exhibits low insertion loss, low power dissipation and high power handling capacity. However, it has several drawbacks such as relatively small bandwidth.

Circulator high power capacity has been used in the microwave and millimeter-wave systems to de-couple the transmitted and received signals. In a continuous wave (CW) radar system, the high-power circulators work as diplexer allowing the transmitter and the receiver to share the same antenna.

There are different types of circulator high power devices, but the popular ones are:

  • – High-power drop-in circulator-suitable for VHF to Ku Band @ Kilowatt power
  • – The UHF circulators-low-loss circulators with efficient heat transfer.
  • – Circulator high power in coaxial and waveguide formats for different circuit designs.
  • – High power broadband ferrite circulator-used for air traffic surveillance.

Raditek offersthe widest range of Circulator high power devices available in the electronic industry see the Raditek website.

SSPA – A Key Electronic Device

SSPA is a device used to increase the magnitude of the signal received from the input mode. In other words, the power amplifier infuses the weak input signal with power as a result the output power load is greater than the input load.

Solid-state power amplifiers are specifically used in all the applications that need amplification of signals, current, voltage, and power, as a prerequisite for further stages of its process.

Communication devices on board a ship, radars, precision equipment, and deep space communication application, all incorporate solid-state power amplifier at various stages of its system.

Recent advances made in field of solid-state technology have enabled the SSPA to be the most viable device vis-à-vis the traveling wave tube amplifiers (TWTA).

Reason being, the solid-state power amplifier is fitted with advanced Gallium Arsenide (GaAs) or Gallium Nitrate (GaN) based transistors and these transistors are the real workhorses of an amplification system.

Further, these amplification systems exquisitely supported by superior design and compatible hardware material ensures the least components breakdown in modern SSPA systems.

Nevertheless, these modules/systems are amenable to repairs and replacements that minimize the maintenance load and time required.

Modern-day advanced SSPA displays its performance parameters on the built-in alpha-numeric dashboard and the same can also be remote-accessed using its tele-interface mode.

The latest SSPA is a superior electronic device in terms of its performance linearity, its size, weight and volume, superior built-in monitoring & alert systems, heat related auto-shutdown system to prevent breakdown and failures. See the Raditek website.

Bandpass Filter – Frequency Patrol Picket

Band pass filter is a frequency patrol picket in an electronic device. This “picket” would allow frequencies of a certain-calibrated/desired-bandwidth to pass through and prevent the unsolicited signals from getting through for further process.

Band pass filter is used in wireless communication transmitters and receivers. Rejection of non-calibrated frequencies helps the transmitter to limit the bandwidth of the output signals to the band allocated for the said transmission.

As a result, the transmitter in use is prevented from interfering among itself at one station and of the other stations too.

There are two types of band-passes-1) Narrow Band Pass and 2) Wide Band Pass. The narrow band-pass filter has a bandwidth small to the average frequency of the band and if the quality factor value is less than 10, it is a wide bandpass.

Further, band pass filter has two categories. 1) Active Band pass and 2) Passive Band pass.

Active bandpass has active components like operation amplifier (Op-Amp) along with resistors and capacitors. Passive band pass uses passive components resistors, capacitors, and inductors-Inductors are not used in active bandpass.

Ideal band pass filter would have a flat band and completely block frequencies outside the calibrated bandwidth-with no gain/attenuation across.

Practically, however, no bandpass is ideal as it doesn’t completely eliminate signals just outside the permitted bandwidth. This is known as filter roll-off.

However, designers/manufacturers succeed in keeping the roll-offs are kept as narrow as possible for the band pass filter to operate as per design. See the Raditek website.

Raditek – Where Quality Beckons

Raditek is a trusted electronic brand name for components, appliances, and equipment used in the global wireless and microwave telecommunication applications.

Raditek came into existence in1993 and with a clear focus on quality products, continuous innovations, and applications the based approach has yielded them high performing and durable products looked up to by the telecommunication industry.

Never judge Raditek products basis its lower price.  It is their core engineering competencies that enable this company to offer unmatched quality components and equipment at a lower price.

Raditek works to ISO 9000 standard.

Visit its online store at here for overstock deals 25 to 75% below list price

Raditek’s several R&D facilities focus on “out of the box research” where top-notch scientists and engineers pool in their expertise to spearhead high-end breakthrough telecom components and equipment used in applications like satellite ground stations, TV/ Radio transmitters, and high-end navigation systems.

Raditek also specializes in advanced FPGA-field programmable gate array-systems. Its products have a global presence leveraged through a robust network of distributors and integrators.

It enjoys the reputation of being “The designated supplier” to the US armed forces for its national and overseas operations.

Its products enjoy unprecedented acceptance and customer loyalty.

The Ingenious Flexible Waveguides

Flexible waveguides are structures that guide electromagnetic waves in one calibrated way with minimal loss of energy or signal strength.

Without the curtailment of waveguides, the amplitudes decrease as it traverses a three dimensional space-as stated by the inverse square law.

Often referred to by the portmanteau as “flexiguides”, they are used to connect two elements using two rigid wave guides system together, particularly when they cannot be located or positioned.

Flexible waveguides are made up of helically wound silver-plated brass strips and the required mechanical support is made available by the protective jacket. It is a thin-walled guide tube pressed to into shape to form convulsions which allow it to flex.

There are 3 main types of flexible waveguides and they are 1) Flexible and twistable 2) Flexible only and 3) Flexible/seamless.

Flexible twistable waveguides are reputed for the best twistable performance among all flexibles though is not recommended for passive intermodulation applications.

Flexible-only waveguides are wound and have a soldered interlock which obliterates RF and pressure leakage. A pre-set twist can be accommodated during its manufacturing stage.

Flexible/Seamless waveguide is used where pressurization is involved as its structure has no soldered joints, hence totally secured.

Flexible waveguides can be manufactured as straight sections that may eventually be bent into shape, as a pre-formed section to be jacketed into defined shape or hybrid sections with flexible and rigid sections.

Specific fabrication of rectangular and double ridge waveguide size is also possible if needed.

Raditek offer high quality for multi-applications see website.

Vital Powerful and Dynamic Component – Microwave Amplifier

Microwave amplifiers are electronic devices capable of increasing the power of an RF signal. It is a two-port device that intensifies the amplitude of signals received from its input terminals and relays them to the output port. The quantum amplitude increase is called “Gain”.

Microwave amplifiers can be a separate individual device or be built-in a part of another device.

The amplification process is fundamental to electronic circuitry and is used in almost all the electronic equipment.

These are solid-state amplifiers that handle a frequency range of 1 to 100GHz and are extensively used in Electromagnetic Compatibility systems (EMC), Electromagnetic interference (EMI), Defense systems, Medical and diagnostic systems, laboratory and field testing appliances.

Modern day microwave amplifiers systems use transistor made of Gallium Arsenide (GaAs) or Gallium Nitrate (GaN) which actually amplifies the signals. GaAs transistor-based amplifiers give the best linearity and the GaN transistor-based amplifiers have the best of efficiency.

There are FETs, IMPATT diode-based microwave amplifiers which work well for lower frequencies and for power levels down to the level of watts.

There are basically 4 different types of microwave amplifiers based on the roles they play in a superheterodyne receiver of radars systems, electronic warfare scanner or a testing instrument.

Application requirement drives the amplifier selection and therefore it is prudent to make application-based selection for optimal results.

Raditek Inc offers a full selection, see website.

The Frequency Nexus

A Waveguide rotary joint is a component in a microwave communication system which is used to connect two different radio frequency waveguides.

Waveguide rotary joint or WRJ in electronic phraseology is a component used to pass on the microwave energy-frequency-from the stationary lines to rotating lines. They are also known as rotating couplers or RF rotary joints.

They are made of two waveguide-to-coaxial transitions which are connected by a coaxial line. As axial cables are circular, the WRJ can rotate about it without hindering its performance.

Waveguide rotary joint differs among themselves in terms of physical dimensions, cross-sections and material used for its fabrication. It is noticed that most WRJ are rectangular, circular, or elliptic cross-sections. The most common materials used to fabricate a WRJ are aluminum, brass, bronze, copper, and silver.

However, WRJs are also made of stainless steel and specialty steels or caparisoned bi-metallic alloys. Dimensional details are the other parameters to consider for the said component.

Specifications of the waveguide rotary joint can vary depending upon the market being serviced by the manufacturers. However, WRJs are manufactured in accordance with the international electro-technical commission (IEC) standards. WRJs are also manufactured in accordance with the US military specifications.

It is important to take into account the general features before one narrows down the selection of WRJS. These features are single, double and quad-ridge has 1, 2 and 4 apertures respectively.

Some waveguide joints are flexible while others are twistable that interface with the circuitry through appropriate connectors. Raditek offers a whole range of these on its website.

OCXO – The Frequency Sustainer

OCXO stands for Oven controlled crystal (Xtal) oscillator. These are used in devices or  pparatus where a high degree of frequency stability is required.

An oven-controlled crystal oscillator or OCXO is a device that has higher frequency stability.

It is an oscillator, where a crystal oven is used to maintain the quartz crystal, in an oscillator, at calibrated constant temperature. Controlled temperature of quartz crystal helps prevent changes in the frequency that arise due to changes in the ambient temperature.

In spite of quartz having a very low thermal expansion, temperature change remains the prime cause of the minor frequency variation in an OCXO.

It is pertinent to note that the drift in the crystal frequency can also be further controlled by giving the crystal an appropriate “Cut”, in other words, trim it to size and shape-to attain its optimum vibrating stability. An SC cut is the best.

OCXOs are expensive and larger as compared to other crystal oscillators and use power to heat the oven therefore not used in battery-operated circuits. However, the frequency stability offered by OCXO is substantially superior to the conventional oscillators.

Such exceptional frequency stability is required for radio transmitters, cell towers, military communication equipment, and precision frequency measuring equipment.

OCXOs are available in different types of packages and different package styles, and prices. Further, its performance may vary basis the type of OCXO needed to be used.

It is recommended to carry out recalibrations and checks-on crystal and heat element aging to ensure that the device performs at its best at all times.

Raditek offers a whole range of these on its website with stability to 0.1ppm

LNB the Crucial Satellite TV Transmission Device

Low Noise Block Downconverter – LNB – also called a low noise block – is a receiving device that is fitted on satellite dish antennas for satellite TV reception.

It collects radio frequency waves beamed by a relevant satellite, on the dish antenna, and converts them into signals to be sent through coaxial cable to the receiver or a set-top box placed indoors of a home.

The set-top box powers the LNB, using the same coaxial cable, which feeds the dish antennas signals into it. It is the front section of a satellite receiver which down converts the block of frequencies to lower block of intermediate frequencies (IF).

The down-conversion of the signals is crucial for it to be carried to the indoor satellite TV receiver-through coaxial cable.

If original satellite signals were to be used straightaway for TV transmission, it would require the use of an expensive waveguide technology which is impractical. And therefore, the use of LNB gains significance.

Further, Intelligent designing techniques and the use of expensive and high-performance components such as HEMTs reduces the noise generated by LNBs which makes it a perfect choice for satellite TV transmission system.

Among the different types of low noise block downconverters, widely used are 1) the Multi-output and 2) Quattro LNBs, for DTH TV systems.

Multi-output LNB’s are a single feed horn with multiple ports for multiple tuners. The Quattro LNB is used for a shared dish antenna system to deliver signals to multiple users. Many models are available from RADITEK Inc. with details on the website.