As with surface mount bias tees, connectorized bias tee modules are built using Marki’s proprietary wirewound coil technology. Precision assembly allows for ultra-broadband resonance free operation in two different models. The BT models offer the lowest frequency coverage down to 4 kHz using large integrated inductors. The more compact BTN models offer the same high frequency coverage without the large integrated inductors. These models are all capable of 500 mA of DC current, up to 30V of DC bias voltage, and 1 watt of RF power.

There are two major limitations on the DC power handling of a bias tee: the voltage rating of the DC blocking capacitor and the current handling capability of the wirewound coil. Marki high power bias tees use high voltage blocking capacitors, which are more prone to resonance due to parasitic inductance. In addition to DC voltage, these capacitors allow high RF power of 10 watts for lower frequency and 5 watts for higher frequency bias tees. These bias tees also use proprietary wirewound coils with thick wire allowing for higher current capability.

Marki uses proprietary design techniques and software to create the highest performance directional couplers in the world. These couplers are based on industry standard triplate stripline construction techniques, making them suitable for high reliability applications. Each coupler is bidirectional, meaning that it can be used in both the forward and reverse direction when the coupled ports are terminated with 50Ω circuits, either loads or detectors. Some models come with one port terminated in a 50Ω load, while most have both coupled ports available. They have been tested to 50 watts of input power (see this tech note) and are suitable for load-pull testing, output power monitoring, and other broadband applications. Custom designs are possible for high volume requirements.

Low insertion loss couplers are perfect for load-pull and other test applications that are sensitive to loss or use high powers. Marki uses two types of construction for low loss couplers. High power stripline couplers use wider traces and thicker circuit boards than our standard stripline directional couplers, but their multisection design provides low loss but with a flat coupling value across the band. Airline directional couplers, as the name implies, use air as the dielectric material. This provides the lowest possible loss and correspondingly highest power handling, but with a coupling factor that varies across the band. These couplers are ideal for low loss or high power applications where the coupling factor can be calibrated out. Power handling of both types of couplers is limited by the connectors, which are available in N, APC-7, SMA, 2.92, and 2.4mm for different models of coupler.

While our stripline directional couplers are bidirectional and can measure power in both directions with 50Ω detectors, there are some applications that use non-50Ω power detectors. For these applications a dual directional coupler allows the user to measure power in both the forward and reverse directions without degradation in directivity due to impedance mismatch presented by the power detector. A dual directional coupler is two bidirectional couplers fabricated back to back, making each coupler insensitive to the non-50Ω coupled port termination.

A pick off tee is a resistive circuit that provides non-directional coupling of microwave signals. Due to reflections, a directional coupler is preferred for most applications. In an extremely well matched system a Marki pick off tee can provide extremely broadband signal monitoring in a very small package.

Marki equalizer modules provide broadband equalization with return loss, low minimum insertion loss, and flat group delay. In addition, the MEQ products are available as a small form factor wire bondable chip, economically priced for high volume applications.

A highpass filter will reject signals with frequency below their designed frequency of operation, and pass all signals above this. Important specifications include rejection of low frequency signals, insertion loss, return loss, and insertion loss flatness above the 3 dB cutoff frequency. Marki highpass filters are based on a cavity design that offers operation to very high frequencies with broad, resonance free passband and stopbands.

A bandpass filter is capacitively coupled between the two ports, offering rejection of both low frequency and high frequency signals and selecting a particular band referred to as the ‘passband’. Important specifications include the center frequency, passband (expressed either as start and stop frequencies or as a percentage of the center frequency), rejection and steepness of rejection, and width of the rejection bands. All bandpass filters will have re-entrant modes at higher frequencies, so the width of the high frequency rejection band is an important consideration. Marki bandpass filters are microstrip filters that are CAD optimized and built on a low loss substrate, offering extremely broad rejection bands.

Diplexers Features

• High Isolation
• Reentrance and Resonance Free Passbands
• Reflectionless termination of unwanted harmonics
• Broad, high frequency passbands

A diplexer is a three port device that combines or divides a common signal according to frequency, into low pass and high pass ports. Unlike a duplexer, which combines two bandpass filters, diplexers are very broadband. Important specifications include frequency coverage, out of band rejection for the high/low pass filters, isolation between the high/low pass filters, insertion loss, and return loss. Marki diplexers offer extremely broad, resonance free passbands. Diplexers can be used as low loss combiners or dividers for signals with different frequencies or as reflectionless filters (with one port terminated) at the output of mixers and other nonlinear devices with many harmonics.

The DMX-64 is the high speed ADSANTEC 5190B SiGe 1 :2 demultiplexer (DEMUX) chip in a connectorized module. The demultiplexer is a broadband 1:2 deserializer that converts a DC to 64 Gb/s input signal into two half rate output signals using a half rate clock. The DMX-64 can be operated single ended or differentially. The DMX-64 is suitable for laboratory testing and use in test equipment.

These mixers offer the best tradeoff between performance, size, repeatability, cost, and lead time/availability, particularly for higher volume applications. Marki develops MMIC and Microlithic® mixers using full electromagnetic and circuit based non-linear optimization. Our MMIC mixers are fabricated with precise tolerance on a GaAs substrate with high speed Schottky diodes. Marki MMIC mixers offer superior non-li+A1:C7ear performance and isolations compared to both competing MMIC mixers and hybrid mixers. Microlithic® mixers offer low, repeatable conversion loss performance. MMIC/Microlithic® chip/module mixers are designed as a small form factor chip. This chip is also packaged into a module that is suitable for high performance laboratory use or as an eval module with equivalent performance as the chip.

The T3 mixer is the most advanced mixer circuit available in the world. In addition to broadband overlapping LO, RF, and IF bands, it has the potential for extremely high linearity. T3 mixers are built using both hybrid constructions that create ultra-broadband coverage on all three ports (RF,LO, and IF) and in MMIC form as the MT3, which offers the scalability of a MMIC with the linear performance of the T3.

Since it is a true-commutating mixer, it will provide increasing two-tone intermodulation suppression, input 1-dB compression, and spurious suppression (for most spurs) as the rise time of the LO signal is increased by either increasing sine wave LO drive or using a square wave LO. Much more detailed information about the T3 can be found in our T3 Tutorial.

IQ Mixers
An IQ mixer consists of two mixers where the RF (or LO) ports are connected with an inphase power divider and the LO (or RF) ports are connected with a quadrature hybrid. The two IF ports, I for the in-phase component and Q for the 90° out-of-phase component, are available to the user. This combination allows the in-phase and quadrature components of the output signal to be modulated independently with each IF port. If an IQ mixer is used to transmit data, the in phase and quadrature components can be selected at the receiver by using another IQ mixer.

Image Reject (IR) and Single Sideband (SSB) Mixers
If the IF ports of an IQ mixer are combined with another quadrature hybrid, the result is a three-port device alternately called an image reject mixer (when used as a downconverter) or single sideband mixer(when used as an upconverter). This structure will reject one sideband when used as a downconverter and will preferentially produce one sideband when used as an upconverter. Selection of either the lower sideband or the upper sideband depends on the orientation of the IF quadrature hybrid relative to the I and Q ports. For extensive analysis of IQ, IR, and SSB mixers see the mixer basics primer and our tech note series on this topic.

Marki’s legendary hybrid mixers offer low conversion loss, isolation, and low LO drive capability across incredible bandwidths. While they have been surpassed in nonlinearity performance by T3, MMIC, and Microlithic^® designs in smaller form factor chip and surface mount packages, legacy mixer connectorized modules are still a sound choice for legacy systems and laboratory use.

M1 double balanced mixers have excellent isolations and conversion loss to 26 GHz. M2 triple balanced mixers offer ultrabroadband overlapping frequency coverage on all three ports. M4 diplexed IF mixers have very broadband RF/LO frequency coverage with low IF frequencies, excellent for test and measurement applications.  M8 mixers offer high isolations and very low conversion loss using a specially balanced technique. M9 millimeter wave double balanced mixers offer high frequency RF/LO coverage to 65 GHz with high IF frequencies.

Our active doublers and quadruplers integrate amplifiers with our doublers, creating an integrated LO multiplier chain in a single module. They are a convenient alternative to expensive synthesizers for use in the laboratory or bolt together systems.

A nonlinear transmission line is a transmission line with nonlinear elements on it (such as Schottky diodes) that create higher harmonics of the signal as it propagates down the line. This process efficiently creates all harmonics of the fundamental signal, leading to the term ‘comb generator’ for the appearance of all the harmonics on a spectrum analyzer. NLTLs accomplish this with very low additive phase noise relative to other devices. NLTLs are an excellent alternative to step recovery diodes.

Marki’s legendary hybrid doublers offer low conversion loss, high suppressions, and low drive capability across incredible bandwidths. While they have been surpassed in suppression performance by MMIC and Microlithic® designs in smaller form factor chip and surface mount packages, legacy mixer connectorized modules are still a sound choice for legacy systems and laboratory use.

A Wilkinson power divider offers the lowest insertion loss (ideally 3 dB, or just the splitting loss) from DC to very high bandwidths. It will also offer isolation across a narrower bandwidth. Marki Wilkinson power dividers offer isolation across extremely broad bandwidth ratios, up to 65:1. As discussed in our tech notes, the required specifications and capabilities for a Wilkinson for power handling and isolation can vary dramatically depending on the application. See our tech notes or contact Marki for further information or to discuss your specific application.

Marki offers unique 1:3 Wilkinson power dividers based on advanced circuit analysis techniques. While three way Wilkinson power dividers are theoretically easy to design, they are very difficult to realize due to the impedances necessary. Extensive experimentation and analysis have allowed Marki to realize 1:3 Wilkinsons across broad bandwidths.

Marki 1:4 Wilkinsons are realized as a cascade of two 1:2 Wilkinson power dividers. By integrating them together into a single package, Marki is able to optimize the interconnects for minimum insertion and return loss.

A resistive power divider is the smallest, simplest, and most broadband type of power divider. However, due to the high insertion loss and lack of isolation it is rarely the best choice for a given application over a Wilkinson power divider. See our tech notes or contact Marki for further information.