Application Notes for Microwave Phase Shifter
The Model 7218 is the latest addition to the family of high performance I.Q. Vector Modulators. Its broadband capability is ideally suited for today’s more demanding and complex Electronic Warfare systems.
The Model 7218 covers a frequency range of 2 to 18 GHz, is capable of a full 360 Degrees phase control and a minimum of 20 dB amplitude control. Response time is 1 microsecond, maximum. Digital control is accomplished by two 12 bit TTL inputs, for I and Q channels, which provide for high precision calibration of phase and amplitude. Operation is guaranteed to be monotonic.

 Broad Frequency range  2 to 18 GHz
 Simultaneous control of phase and amplitude
 Digitally programmable  12 Bits for both I & Q
 High Speed
 Guaranteed monotonic

THEORY OF OPERATION The block diagram of the microwave IQ Vector Modulator is shown in Figure 1. An RF signal incident on a 3 dB quadrature hybrid is divided into two equal outputs, with a 90° phase difference between them. The inphase, or 0°, channel is designated the I channel and the Quadrature, or 90°, channel is designated the Q channel. Each signal passes through a biphase modulator which sets the 0° or 180° state and the attenuation level for both the I and Q paths. The outputs of the I and Q path are combined to yield the resultant vector which may fall anywhere within the bounded area shown in Figure 2. Any signal applied to the I?Q Vector Modulator can be shifted in phase and adjusted in amplitude by applying the following relationships:
1. Let the desired attenuation level = X dB and the desired phase shift = θ° (with respect to 0 dB and 0° reference states). 2. The normalized output voltage magnitude is given by: ? V ? = 10^{?(x/20)}. 3. The values of the I and Q attenuator control inputs are then expressed as:
Q = V sin θ.
Figure 3 shows the nominal value of I and Q vs. either digital word (Series 71) or analog voltage (Series 72). Thus, to achieve an attenuation level of 3 dB with a phase offset of 112.5° (with respect to 0 dB and 0° reference states) the values of I and Q can be calculated as follows:
V = 10^{–(3/20)} = 0.707 I = 0.707 cos (112.5°) =–0.027 Q = 0.707 sin (112.5°) =+0.65
From Figure 3, the control inputs to yield the desired amplitude and phase are approximately:
Analog Units (72 Series) Digital Units (71 Series) I = 5.78 volts 100101000000 Q = 2.84 volts 010010001011
While these values for I and Q will yield an output signal whose amplitude and phase are close to the nominal values over the entire operating frequency range of the vector modulator, the use of an iterative measurement procedure will determine the I and Q inputs which exactly define the desired parameter at any selected frequency.


PERFORMANCE CHARACTERISTICS
PARAMETER

SPECIFICATION 
OPERATING FREQUENCY RANGE 
2.0  18.0 GHz 
Band 1

2  6 GHz 
Band 2

6  18 GHz 
Band Switching Speed,max 
250 nanoseconds 
INSERTION LOSS (MAX) 
16 dB 
VSWR (MAX) 
2.2:1 
POWER HANDLING CAPABILITY 
Without performance degradation

+20 dBm 
Survival 
1 W 
ABSOLUTE INSERTION PHASE ACCURACY VS. FREQUENCY (MAX) 
±15^{o} (in each band) 
VARIATION OF PHASE VS. TEMPERATURE (MAX) 
±0.1 deg./ ^{o}C

ATTENUATION RANGE (MIN)

20 dB

VARIATION OF AMPLITUDE VS. TEMPERATURE (MAX)

0.02 dB/ ^{o}C

RESPONSE TIME (MAX)

1.0 µsec

POWER SUPPLY

+5 V ±2% @ 200 mA, max. +12 to +15V @ 150 mA, max. 5.2 V ±2% @ 400 mA, max. 12 to 15V @ 150 mA, max

MONOTONICITY

GUARANTEED

Control INPUT

12 BIT TTL FOR BOTH I & Q INPUTS

CONNECTORS

RF Input/output

SMA Female, 2X

Control/Power

Cannon DC37P or Equivalent

TEMPERATURE RANGE

Operating

55 ^{o}C to +85 ^{o}C

Storage

65 ^{o}C to +125 ^{o}C

ACCESSORY FURNISHED 
Mating power/control connector

AVAILABLE OPTIONS 
Option No.

Description

G09

Guaranteed to meet Environmental Ratings 
G12

RoHS Compliant 
G16 
RoHS Plus REACH Compliant 


DIMENSIONS AND WEIGHT
J3 PIN FUNCTION 
PIN 
FUNCTION 
PIN 
FUNCTION 


19 
Q9 
1 
I5 
20 
I4 
2 
I6

21 
I7 
3 
I8 
22 
I3 
4 
I9 
23 
I2 
5 
I10 
24 
I1 (LSB) 
6 
I11 
25 
I12 (MSB 
7 
BAND 1 (notes 1 & 2) 
26 
N/C 
8 
+12 to +15V 
27 
+5V ±2% 
9 
GND 
28 
GND 
10 
GND 
29 
BAND 1 (notes 1 & 2) 
11 
12 to 15V 
30 
5.2V ±2% 
12 
Q3 
31 
BAND 2 (notes 1 & 2) 
13 
Q2 
32 
Q4 
14 
Q1 (LSB) 
33 
BAND 2 (notes 1 & 2) 
15 
Q5 
34 
N.C. 
16 
Q6 
35 
Q12 (MSB) 
17 
Q7 
36 
Q11 
18 
Q8 
37 
Q10 

NOTES: 1. BAND SELECT: Band 1 (2 to 6 GHz)  Apply TTL 0 to Pin 7 or Pin 29 Band 2 (6 to 18 GHz)  Apply TTL 0 to Pin 31 or Pin 33 2. With no band selected, there will be maximum Isolation between J1 and J2
