UM9601_06 Datasheet, PDF (11/16 Pages) Microsemi Corporation – FOR MICROSTRIP 900 MHz ANTENNNA SWITCHES

UM9601 – UM9608
FOR MICROSTRIP 900 MHz ANTENNNA SWITCHES
C OS O S
AND MICROWAVE APPLICATIONS
ISOLATION vs FREQUENCY AND DIODE CURRENT
0.025" (0.635mm) ALUMINA MICROSTRIP SPST SWITCH
TYPICAL
28
UM9601 - UM9604
26
1 GHz
24
UM9605 - UM9608
22
20
UM9601 - UM9604
18
3 GHz
16
UM9605 - UM9608
14
12
10
8
6
10
100
1000
DIODE CURRENT (mA)
Installation in Microstrip
The cup type flange on the UM9601, UM9602, UM9605, and
UM9606 is designed to be affixed to the ground plane surface
of a microstrip board. The UM9603, UM9604, UM9607, and
UM9608 were designed to be affixed to a backing plate as
shown. It was experimentally determined that at frequencies
greater than 2 GHz the anode of the diode should be
approximately 0.010” (.254mm) above the top surface of the
microstrip for lowest insertion loss.
Figure: UM9601/UM9602 Microstrip Mount
Design Example – 900 MHz Antenna Switch
An example of a practical circuit design using a UM9601
diode is a quarter-wave antenna switch covering the frequency
of 800-900 MHz. The circuit design for this switch is shown
and was constructed using 0.025” (0.645mm) alumina
microstrip.
This antenna switch uses a series mounted diode and a shunt
mounted diode. The UM9601 was selected for shunt mounted
device (SPST performance at 1 GHz: 0.2dB insertion loss and
25dB isolation) and because it is the lowest cost diode in the
UM9601-UM9608 series. A UM9401 axial lead diode was
chosen for the series mounted device.
The performance of this switch is displayed in the graphs
and in the following table. It should be noted that the loss
values are actual measured numbers including losses due to the
capacitors, bias networks, connectors, as well as the board. In a
typical radio application where the antenna switch circuit board
is integrated in the same microstrip board that contains
transmitter and receiver elements the connector loss is
eliminated. This will result in lower overall insertion loss values
than indicated here.
For solder adhesion the microstrip may be heated to solder
melting temperature (up to 300 ^oC) with no damage to the
diode. Conductive epoxy may also be employed. The thermal
resistance of solder mounted UM9601-UM9604 in their test
boards was less than 20 ^oC/W; for the UM9605-UM9608
thermal resistance was less than 30 ^oC/W.
Copyright  2005
Rev. 0, 2006-01-17
Microsemi
Page 11