Description

Advanced Microwave, Inc. is entering into a new era of microwave converter technology. Our emphasis is on using the latest technology available and designing the product to manufacture at a low cost while maintaining the reliability of the product at its best.

The Advanced Microwave Mixer offers an ultra wideband matching structure with a quad matched monolithic Schottky barrier diode, resulting in a broad band mixer with low conversion loss and low spurious response. The planar construction allows optimum phase and amplitude matching and tracking over a wide frequency range.

Our Mixer Preamplifier uses the same mixer technology with the addition of some filtering and wideband RF and microwave amplifiers. The amplifiers are designed to have a flat response over the specified frequency range, high intercept point and high gain. They are also designed for good temperature compensation. The addition of a filter has made it possible to have good isolation from LO to RF to IF.

Our Image Reject Mixer uses the same mixer technology with the addition of a power divider and a 90 degree coupler. This product is designed to be rugged and low cost. Each frequency band has a specific quad coupler designed for the band to get optimum image rejection.

Our Microwave Amplifiers are ideal for wireless communication products. They are designed in state-of-the-art thin film technology with an emphasis on making them rugged, reliable, and low cost.

Custom Amplifiers with a higher power level or higher gain or wider bandwidth, to meet specific applications or specifications are also available..

Applications

Advanced Microwave converter products are designed to cover a wide range of microwave and RF frequencies. This allows for broader applications for super heterodyne receivers, bi-phase modulation, balanced modulation and QPSK modulation.

Super heterodyne receivers are usually double or triple conversion receivers used in narrow band applications and in the presence of many undesirable RF and microwave signals. Most of the filtering is done at lower frequencies, which results in a high quality desirable signal. A double balanced mixer or mixer pre- amplifier is ideal for the front end of this type of receiver.

Advanced Microwave mixers can also be used for biphase and pulse modulation where the carrier signal is fed into LO and the modulated signal will appear at the RF port when a bipolar signal is fed into the IF port. The phase of the output signal will shift to 180 degrees when a reversal of polarity occurs. The current into the IF port is limited to 25 milliamps.

Image Reject Mixers historically are used in direct digital communication, specifically for telecommunication. Where there are many signals combined at the base-band in a digital format then modulated using quadra phase shift keying modulation (QPSK). There are two IF ports for the Image Reject Mixers with 90 degrees out of phase. The base-band signal is injected or received at the IF ports, then multiplexed or demultiplexed into many channels.

To get good spectral purity is to have LO as the driver and IF, Sin X, and Cos X. However, sometimes the IF is used as the driver with 20 to 25 mA maximum current, but the 2nd and 3rd overtone will be somewhat higher than the initial approach.

Advanced Microwave, Inc. offers two standard packages; one is a popular coaxial package and the other is a drop in surface mount package requiring proper assembly to obtain the specified performance, particularly at frequencies above 12 GHz.

Microwave Amplifiers are used when a better noise figure is required or a higher intercept point is needed for converters.

Contact the factory for other specifications or additional detailed technical information.

Frequency Converter/Amplifier Definitions

Conversion Loss (Gain): The ratio (in dB) of input power relative to the frequency converted to output power. For up conversion F_L + F_I = F_R . For down conversion F_L - F_R = F_I or F_R - F_L = F_I .

Noise Figure: The signal to noise ratio at the input divided by the signal to noise ratio at the output. Typically, a single sideband noise figure is 0.5 dB higher than the conversion loss of the mixer, however, the noise figure for a mixer preamplifier is also dependant on the amplifier noise figure.

Isolation: The ratio (in dB) of input power relative to the output power of the same frequency at any other ports is called isolation. For a double balanced mixer, the isolation is a reflection of phase and amplitude within the mixer.

1dB Compression Point: The input power at which the conversion loss is 1dB higher (or the conversion gain is 1dB lower) than the low level input signal at the same frequency. The low level signal is considered to be 10dB or lower than the 1dB compression. Conversion loss (or gain) remains constant over the full low level dynamic range at the same frequency for mixers and amplifiers.

Third Order Intercept: A mathematical analysis of the difference between the second harmonic of one signal and the fundamental frequency of the other signal ( 2·f₁ - f₂ or 2·f₂ - f₁ ) is called third order intermodulation. The third order intercept point is calculated as follows:

IM₃ = 3·P₀ - 2·P_i
P_i = output intercept point
P₀ = output power (for devices having gain)
P₀ = input power-conversion loss (for devices having loss)

The third order intercept point is generally about 10 dB higher than the 1dB compression point. The diode barrier level determines the 1dB gain compression point and third order intercept point of the device for mixers.

Intermodulation Product: Since a mixer is a nonlinear device which results in an intermodulation product, and one of the three ports of the mixer has to drive it into saturation to generate a consistent conversion loss over the full dynamic range, the mixer generates odd harmonics and low level even harmonics once any one port is driven into saturation. For a mixer with perfect symmetry and a well-matched quad diode even harmonics are low.

Typical intermodulation product in dBc:

	L	2L	3L	4L
R	X	40	30	50
2R	45	45	40	60
3R	40	50	45	65
4R	50	60	55	70

For an RF level of 10 dB or more below the 1 dB gain compression point. Note: This table applies only for mixers and may differ for mixer preamps.