Microwave Electronics Products

Microwave Attenuator: Models 1959, D1959

Application Notes for Microwave Attenuators

MODEL 1959

The Model 1959 is a current controlled attenuator/modulator that provides a minimum of 50 dB of attenuation over the frequency range of 18 to 40 GHz. As shown in figure 1 below, the RF circuit uses two shunt arrays of PIN diodes and two quadrature hybrid couplers. The quadrature hybrids are of a unique GMC microstrip design which are integrated with the diode arrays to yield a minimal package size.

MODEL D1959

The Model D1959 voltage-controlled linearized attenuator/modulator is an integrated assembly of a Model 1959 and a hybridized driver circuit which provides a nominal transfer function of 10 dB per volt. (See figure 2 below.)

Model 1959 RF schematic diagram 
  • Absorptive
  • Current or voltage controlled
  • 18 to 40 GHz frequency range
  • High performance MIC quadrature hybrid design
  • High speed

Microwave Attenuator Model D1959

Model D1959 block diagram Model 1959 typical effects of temperature on attenuation
PERFORMANCE CHARACTERISTICS
MODEL

FREQUENCY RANGE (GHz)

MAX. INSERTION LOSS (db)

MAX. VSWR

FLATNESS (± dB) AT MEAN ATTENUATION LEVELS UP TO
10 dB 20 dB 40 dB 50 dB
1959 18-26.5 3.6 2.2 1.3 2.2 3.4 4.0
26.5-36 4.1
36-40 4.7
D1959 18-26.5 4.1 2.2
26.5-36 4.6
36-40 5.2

COMMON TO BOTH MODELS 1959 and D1959

Mean Attenuation Range ........ 50 dB
Monotonicity ................................ Guaranteed
Power Handling Capability
    Without Performance
        Degradation ....................

10 mW cw or peak
        Survival Power ................. 0.2W average, 5W peak
(11 µsec max pulse width)
MODEL 1959
Rise and Fall Times
    Rise Time .................................. 75 nsec max
    Fall Time ................................... 20 nsec max(1)
Bias Current for Maximum
    Attenuation ............................... 15 to 70 mA
Temperature Effects ..................

See figure 3

MODEL D1959
Accuracy of Attenuation
    0 to 30 dB .................................. ±0.5 dB
    30 to 50 dB ................................ ±1.0 dB
Temperature Coefficient ......... ±0.025 dB/°C
Switching Characteristics
    ON Time ..................................... 1,600 nsec
    OFF Time .................................. 100 nsec max(1)
Nominal Control Voltage Characteristics
    Operating .................................. 0 to +5V
   Transfer Function .................... 10 dB/volt
   Input Impedance ...................... 10 k ohms
Modulation Bandwidth
    Small Signal ............................ 5 MHz
    Large Signal ........................... 2 MHz
Power Supply
    Requirements ......................... + 12V ± 5%, 120 mA
- 12V ± 5%, 50 mA
Power Supply
    Rejection .................................. Less than 0.1 dB/Volt
change in either supply

(1) For attenuation steps of 10 db or more
ENVIRONMENTAL RATINGS
Operating Temperature Range
    Model 1959 ............................ -54oC to +110oC
    Model D1959 ......................... -54oC to +110oC
Non-Operating
   Temperature Range
.............

-65oC to +125oC
Humidity ..................................... MIL-STD-202F, Method 103B, Cond. B (96 hrs. at 95%)
Shock ......................................... MIL-STD-202F, Method 213B, Cond. B (75G, 6 msec)
Vibration .................................... MIL-STD-202F, Method 204D, Cond. B. (.06" double amplitude or 15G, whichever is less)
Altitude ........................................ MIL-STD-2002F, Method 105C, Cond. B (50,000 ft.)
Temp. Cycling ............................ MIL-STD-202F, Method 107D, Cond. A, 5 cycles
 AVAILABLE OPTIONS
Option No    Description
3 SMA female bias/control connectors
7 Type K male RF connectors
10 One type K male (J1) and one type K femail (j2) RF connectors
61(1) 20 dB/volt transfer function with 0 to +3V control signal input
62(1) ± 15 volts operation
64 SMC male bias/control connectors
64A A SMB male bias/control connectors
 

(1) Not applicable for units without drivers

DIMENSIONS AND WEIGHT

Model 1959 Dimensions and weight Model D1959 dimensions and weight
Dimensional Tolerances, unless otherwise indicated: xx ±.02; xxx ±.005