Antenna system modeling using "spice-like" syntax

Spice uses a generalized notation to define the system in terms of connections between nodes:

<type><id> <from node> <to node> <value>

R1 1 5 12K is a Resistor (R), number 1, connected from node 1 to node 5, with value 12K.

So, we have R, L, C, X

A few "special" things need to be defined:

Transmission lines

Which are modeled as a pi network (conveniently for admittances)

(except we'll change the Z to Y for the drawing)


Arrays of radiating elements

modeled as a bunch of admittances interconnecting the nodes. The following figure shows what it would look like for a 4 element array. We assume, for now, that the network is reciprocal, so there's only 10 unique values in a 4x4 square matrix (that is, Y23 = Y32).

So, here's a notional model of a 4 element array, with pi networks at the feed points, transmission lines. I've used a convention of labeling nodes as:

1-N nodes at the feedpoints
101 to 100+N node at feedline side of matching network, and antenna end of transmission line
201 to 200+N node at radio side of transmission line, and antenna side of phasing network
301 at radio side of phasing network (all joined together)
401 at radio side of matching network

Lp1 1 101
Cp11 0
Cp2 101 0

T1c 101 201 series part of tl model
T1b 101 0 shunt part of tl model (on antenna side)
T1a 201 0 shunt part of tl model (on radio side)

Y11 1 0 value of Y11
Y12 1 2 value of Y12

radio/antenna/phased/spice.htm - 4 April 2006  - Jim Lux
(phased array) (antenna page) (radio page) (Jim's home page)