08.08.2013 Views

Chapter 2 Fast Algorithms for the Electromagnetic Scattering from ...

Chapter 2 Fast Algorithms for the Electromagnetic Scattering from ...

Chapter 2 Fast Algorithms for the Electromagnetic Scattering from ...

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

h <br />

s s<br />

(E ,H )<br />

PEC<br />

Γ<br />

i i<br />

(E ,H )<br />

θ<br />

y<br />

c c<br />

Ω<br />

ε(x,y)<br />

Γ Γ<br />

µ<br />

0<br />

r r<br />

(E ,H )<br />

<br />

ε µ<br />

ka <br />

k a <br />

<br />

ka <br />

<br />

<br />

<br />

<br />

<br />

<br />

k 2 h <br />

<br />

h 1m × 1m <br />

h ≈ 10 −4 m 10 8 <br />

<br />

<br />

<br />

<br />

0<br />

x<br />

0


i.e. <br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

O(M 2 ) M × M


∇ × E = iωµH,<br />

∇ × H = −iωɛE,<br />

ω ɛ µ <br />

<br />

<br />

z <br />

µ = µ0 <br />

ɛ Im(ɛ) ≥ 0<br />

<br />

z E <br />

<br />

∆u + k 2 u = f(x, y), (x, y) ∈ Ω ∪ R + 2 ,<br />

u = 0, (∂Ω\Γ) ∪ Γ c ,<br />

<br />

<br />

√ ∂us s<br />

lim r − ik0u = 0, <br />

r→∞ ∂r<br />

u s R + 2 Γ = (0, a) <br />

r = x 2 + y 2 k 2 = ω 2 ɛµ = k 2 0 ɛrµr k0 = ω √ ɛ0µ0 <br />

ɛr = ɛ/ɛ0 µr = µ/µ0 <br />

f = 0 <br />

f = 0


1<br />

∇ ·<br />

∇u<br />

ɛr<br />

<br />

+ k 2 0µru = f(x, y), (x, y) ∈ Ω ∪ R + 2<br />

, <br />

∂u<br />

= 0, (∂Ω\Γ) ∪ Γc<br />

∂n<br />

z H <br />

n <br />

<br />

i.e. <br />

<br />

u s <br />

Gd(x, x ′ ) = i<br />

<br />

4<br />

H (1)<br />

0<br />

(kr) − H(1)<br />

0 (k¯r)<br />

<br />

<br />

,<br />

∆Gd + k 2 0Gd = −δ(x, x ′ ), x, x ′ ∈ R + 2 ,<br />

Gd = 0, y = 0,<br />

<br />

√<br />

lim r<br />

r→∞<br />

∂Gd<br />

∂r<br />

<br />

− ik0Gd = 0,<br />

x = (x, y) x ′ = (x ′ , y ′ ) r = |x − x ′ | ¯r = |x − ¯x¯x¯x ′ | ¯x¯x¯x ′ = (x ′ , −y ′ ) x ′ <br />

x<br />

<br />

u s <br />

(x) =<br />

Γ<br />

∂Gd(x ′ , x)<br />

∂y ′<br />

u s (x ′ )<br />

<br />

y ′ =0 +<br />

<br />

∂Gd(x ′ , x)<br />

∂y ′<br />

<br />

<br />

<br />

y ′ =0 +<br />

= ik0y<br />

2r H(1)<br />

1 (k0r),<br />

r = (x − x ′ ) 2 + y 2 y y → 0 + <br />

∂u s (x)<br />

∂y<br />

<br />

<br />

<br />

y=0 +<br />

= ik0<br />

2<br />

<br />

Γ<br />

<br />

dx ′ ,<br />

1<br />

|x − x ′ | H(1)<br />

1 (k0|x − x ′ |)u s (x ′ , 0)<br />

<br />

∂us ∂y = IM(u s ) := ik0<br />

2<br />

<br />

=<br />

1<br />

<br />

ds(x ′ ).<br />

Γ |x − x ′ | H(1) 1 (k0|x − x ′ |)u s (x ′ , 0)dx ′ , x ∈ (0, a), <br />

<br />

= Γ


IM(u s ) = ik0<br />

2<br />

<br />

R<br />

<br />

k 2 0 − ξ2 F[ũ s ]e ξx dξ,<br />

ũs us H1/2 (R) F <br />

<br />

<br />

<br />

⎧⎨<br />

∆u + k<br />

⎩<br />

2u = 0, (x, y) ∈ Ω,<br />

u = 0, ∂Ω\Γ,<br />

∂us ∂n = IM(us ), Γ.<br />

uI = e i(αx−βy) α = k0 sin θ β =<br />

k0 cos θ −π/2 < θ < π/2 y <br />

u s <br />

u s = u − uI + e i(αx+βy) ,<br />

u u s <br />

f = 0 u <br />

⎧<br />

⎨<br />

⎩<br />

∆u + k 2 u = 0, (x, y) ∈ Ω,<br />

u = 0, ∂Ω\Γ,<br />

∂u<br />

∂n = IM(u) + gM(x), Γ,<br />

gM(x) = −2βe iαx<br />

u s <br />

Gn(x, x ′ ) = i<br />

<br />

H<br />

4<br />

(1)<br />

0 (k0r) + H (1)<br />

0 (k0¯r)<br />

<br />

<br />

∆Gn + k 2 0Gn = −δ(x, x ′ ), x, x ′ ∈ R + 2 ,<br />

∂Gn<br />

∂n<br />

<br />

= 0, y = 0,<br />

√<br />

lim r<br />

r→∞<br />

∂Gn<br />

∂r<br />

<br />

− ik0Gn = 0.<br />

<br />

u s <br />

(x) = −<br />

Γ<br />

<br />

Gn(x ′ , x) ∂us (x ′ )<br />

∂y ′<br />

<br />

y ′ =0 +<br />

dx ′ .


u s (x, 0) = IE( ∂us<br />

<br />

i<br />

) := − H<br />

∂y 2 Γ<br />

(1)<br />

0 (k0|x ′ − x|) 1<br />

ɛr<br />

∂u s (x ′ )<br />

∂y ′<br />

<br />

<br />

<br />

<br />

y ′ =0 −<br />

IE( ∂us<br />

<br />

<br />

i 1 ∂us ) = − F (y, 0) e<br />

∂n 2π R k2 0 − ξ2 ∂y iξx dξ.<br />

dx ′ . <br />

uI = ei(αx−βy) <br />

<br />

u(x, y)| y=0 + = u(x, y)| y=0 −<br />

<br />

<br />

∂u <br />

<br />

∂n<br />

y=0 +<br />

= 1<br />

ɛr<br />

<br />

∂u <br />

<br />

∂n<br />

y=0 −<br />

<br />

⎧ ⎪⎨<br />

⎪⎩<br />

<br />

1 ∇ · ɛr ∇u<br />

<br />

+ k2 0 µru = 0, (x, y) ∈ Ω,<br />

∂u<br />

∂n<br />

u = IE( ∂u<br />

∂n ) + gE, Γ,<br />

= 0, ∂Ω\Γ,<br />

,<br />

<br />

gE(x) = 2e iαx<br />

<br />

Im(k 2 ) ≥ 0 <br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

{xi, yj} M+1,N+1<br />

i,j=0 Ω = [0, a]×[−b, 0] xi+1 −xi =<br />

hx yj+1 − yj = hy uij (xi, yj)


ui−1,j − 2uij + ui+1,j<br />

h 2 x<br />

+ ui,j−1 − 2uij + ui,j+1<br />

+ k 2 (xi, yj)uij = 0,<br />

u0j = uM+1,j = ui0 = 0, i = 1, 2, . . . , M, j = 1, 2, . . . , N,<br />

h 2 y<br />

(A D x ⊗ IN + IM ⊗ A D y + D)U1 + (IM ⊗ aN+1)u:,N+1 = 0, <br />

⊗ IM M ×M <br />

<br />

<br />

A D x = 1<br />

h 2 x<br />

⎡<br />

⎢<br />

⎣<br />

−2 1<br />

1 −2 1<br />

<br />

1 −2<br />

⎤<br />

⎥<br />

⎦ , ADy = 1<br />

h2 y<br />

⎡<br />

⎢<br />

⎣<br />

−2 1<br />

1 −2 1<br />

<br />

1 −2<br />

D = (D1, D2, . . . , DM) , Di = (k 2 (xi, y1), k 2 (xi, y2), . . . , k 2 (xi, yN)),<br />

aN+1 = 1<br />

h2 eN, eN = (0, . . . , 0, 1)<br />

y<br />

T ,<br />

U1 = (u11, u12, . . . , u1N, u21, u22, . . . , u2N, . . . , uM1, . . . , uMN) T ,<br />

u:,j = (u1j, u2j, . . . , uMj) T .<br />

∂u<br />

∂y <br />

<br />

i.e.<br />

ui,N+1 − uiN<br />

hy<br />

=<br />

M<br />

l=1<br />

1<br />

u:,N + ( 1<br />

h 2 y<br />

hy<br />

g M il ul,N+1 + gM(xi), i = 1, 2, . . . , M,<br />

⎤<br />

⎥<br />

⎦ ,<br />

GM − 1<br />

h2 IM)u:,N+1 = −<br />

y<br />

1<br />

gM, <br />

hy<br />

GM = (g M ij )M i,j=1 <br />

(GM) <br />

<br />

<br />

k (ɛr(x, y)) ≥ 0 <br />

(GM)


A M 11<br />

A M 21<br />

AM 12<br />

1<br />

hy GM − 1<br />

h2 IM<br />

y<br />

U1<br />

u:,N+1<br />

<br />

=<br />

0<br />

− 1<br />

hy gM<br />

A M 11 = A D x ⊗ IN + IM ⊗ A D y + D,<br />

A M 12 = IM ⊗ aN+1, A21 = (A M 12) T .<br />

<br />

, <br />

<br />

i.e. k 2 = k 2 (y) <br />

D = IM ⊗ Dk <br />

Dk = (k 2 (y1), k 2 (y2), . . . , k 2 (yN)).<br />

<br />

<br />

A D x <br />

SMA D x SM = Λ =<br />

SM <br />

S 2 M<br />

SM =<br />

2<br />

M + 1<br />

<br />

sin lmπ<br />

M + 1<br />

M<br />

⎡<br />

⎢<br />

⎣<br />

λ1<br />

λ2<br />

, λl = −<br />

l,m=1<br />

λM<br />

⎤<br />

⎥<br />

⎦ ,<br />

4(M + 1)2<br />

a 2 sin 2 lπ<br />

2(M + 1) ,<br />

= I <br />

Λ ⊗ IN + IM ⊗ (A D y + Dk) Ū1 + (IM ⊗ aN+1)ū:,N+1 = 0, <br />

<br />

Ū1 = (SM ⊗ IN) U1 = (ū11, . . . , ū1N, ū21, . . . , ū2N, . . . , ūM1, . . . , ūMN) T ,<br />

ū:,j = SMu:,j = (ū1j, ū2j, . . . , ūMj) T .<br />

<br />

1<br />

ū:,N + SM( 1<br />

h 2 y<br />

hy<br />

GM − 1<br />

h2 IM)SMū:,N+1 = ¯gM,<br />

y<br />

¯gM = − 1<br />

hy SMgM<br />

<br />

(AD y + λiIN + Dk)ūi,: + aN+1ūi,N+1 = 0, i = 1, 2, . . . , M,<br />

1<br />

h2 ū:,N + SM(<br />

y<br />

1<br />

hy GM − 1<br />

h2 IM)SMū:,N+1 = ¯gM,<br />

y


ūi,: = (ūi1, ūi2, . . . , ūiN) T , i = 1, 2, . . . , M.<br />

<br />

<br />

A D y + λiIN + Dk = LiRi, i = 1, 2, . . . , M,<br />

A D y + λiIN + Dk Li <br />

<br />

Riūi,: + L −1<br />

i aN+1ūi,N+1 = 0, i = 1, 2, . . . , M, <br />

Ri = (ri pq)<br />

<br />

ri NN ūiN + ri N,N+1ūi,N+1 = 0, i = 1, 2, . . . , M,<br />

1<br />

h2 ū:,N + SM(<br />

y<br />

1<br />

hy GM − 1<br />

h2 IM)SMū:,N+1 = ¯gM,<br />

y<br />

<br />

r i N,N+1 L −1<br />

i aN+1 ū:,N ū:,N+1 <br />

<br />

k 2 <br />

h <br />

r i NN = 0, i = 1, 2, . . . , M.<br />

ū:,N <br />

<br />

<br />

( 1<br />

SMGMSM −<br />

hy<br />

1<br />

h2 IM −<br />

y<br />

1<br />

h2 E)ū:,N+1 = ¯gM, <br />

y<br />

( 1<br />

GM −<br />

hy<br />

1<br />

h2 IM −<br />

y<br />

1<br />

h2 SMESM)u:,N+1 = −<br />

y<br />

1<br />

gM, <br />

hy<br />

E =<br />

⎡<br />

⎢<br />

⎣<br />

r 1 N,N+1 /r1 NN<br />

<br />

r M N,N+1 /rM NN<br />

ū:,N+1 Γ <br />

<br />

<br />

(A D y + λiIN + Dk)ūi,: = −aN+1ūi,N+1, i = 1, 2, . . . , M, <br />

1<br />

ū:,N + SM( 1<br />

h 2 y<br />

<br />

<br />

<br />

hy<br />

⎤<br />

⎥<br />

⎦ .<br />

GM − 1<br />

h2 IM)SMū:,N+1 = ¯gM<br />

y


GM<br />

Ri E <br />

<br />

¯gM<br />

ū:,N+1 u:,N+1<br />

<br />

<br />

<br />

A = 1<br />

hy<br />

SMGMSM − 1<br />

h2 IM −<br />

y<br />

1<br />

h2 E.<br />

y<br />

<br />

<br />

<br />

P = − 1<br />

h2 (IM + E)<br />

y<br />

<br />

AP −1 v = ¯gM P ū:,N+1 = v. <br />

<br />

¯gM − AP −1 v p 2<br />

¯gM − AP −1 v 0 2<br />

v p p v 0 <br />

GM <br />

IM(u) GM<br />

<br />

<br />

12M log M A P <br />

<br />

12M log M<br />

<br />

u:,N+1 <br />

<br />

<br />

p <br />

p <br />

<br />

≤ δ,


u f = 0<br />

O(M)<br />

3MN<br />

2M log M<br />

O(12pM log M)<br />

5MN<br />

O(MN) + 12pM log M<br />

<br />

<br />

1<br />

<br />

1<br />

hx ɛr(xi+1/2, yj)<br />

+ 1<br />

<br />

1<br />

hy ɛr(xi, yj+1/2) ui+1,j − uij<br />

hx<br />

ui,j+1 − uij<br />

hy<br />

−<br />

1<br />

ɛr(x i−1/2, yj)<br />

−<br />

1<br />

ɛr(xi, y j−1/2)<br />

uij − ui−1,j<br />

hx<br />

<br />

uij − ui,j−1<br />

+k 2 0(xi, yj)µruij = 0, i = 1, 2, . . . , M, j = 1, 2, . . . , N,<br />

<br />

u1j − u0j<br />

hx<br />

uMj − uM+1,j<br />

hx<br />

ui1 − ui0<br />

hy<br />

= 0, j = 1, 2, . . . , N,<br />

= 0, j = 1, 2, . . . , N,<br />

= 0, i = 1, 2, . . . , M.<br />

<br />

i.e.<br />

<br />

ui,N+1 = 1<br />

hy<br />

M<br />

l=1<br />

1<br />

ɛr(xl, y 1<br />

N+ )<br />

2<br />

gE il (ul,N+1 − ulN) + gE(xi), i = 1, 2, . . . , M,<br />

1<br />

GEDɛru:,N + (IM − 1<br />

GEDɛr)u:,N+1 = gE,<br />

hy<br />

Dɛr = (1/ɛr(x1, y N+ 1<br />

2<br />

hy<br />

), 1/ɛr(x2, y N+ 1<br />

2<br />

hy<br />

<br />

), . . . , 1/ɛr(xM, y 1<br />

N+ )),<br />

2<br />

GE = [g E ij ]M i,j=1 <br />

GE <br />

ɛr = ɛr(y) <br />

<br />

A E 11<br />

A E 21<br />

1<br />

hy G−1<br />

E<br />

A E 12<br />

1 − h2 Dɛr<br />

y<br />

U1<br />

u:,N+1<br />

<br />

=<br />

0<br />

1<br />

hy G−1<br />

E gE<br />

<br />

,


A ND<br />

y<br />

= 1<br />

h 2 y<br />

A N x = 1<br />

h 2 x<br />

⎡<br />

⎢<br />

⎣<br />

⎡<br />

⎢<br />

⎣<br />

− 1<br />

ɛr(y<br />

1+ 1 )<br />

2<br />

,<br />

1<br />

ɛr(y 2− 1 2<br />

A E 11 = A N x ⊗ ˜ Dɛr + IM ⊗ A ND<br />

y + k 2 0µrI,<br />

A E 1<br />

12 =<br />

h2 yɛr(yN+1/2) IM ⊗ eN, A E 21 = (A E 12) T ,<br />

) , −<br />

<br />

−1 1<br />

1 −2 1<br />

<br />

1 −1<br />

1<br />

ɛr(y<br />

1+ 1 )<br />

2<br />

1<br />

ɛr(y<br />

2− 1 )<br />

2<br />

+ 1<br />

ɛr(y<br />

2+ 1 )<br />

2<br />

⎤<br />

<br />

,<br />

1<br />

ɛr(y<br />

2+ 1 )<br />

2<br />

<br />

1<br />

ɛr(y N− 1 2<br />

) , −( 1<br />

ɛr(y<br />

N− 1 )<br />

2<br />

+<br />

1<br />

ɛr(y<br />

N+ 1 )<br />

2<br />

)<br />

⎥<br />

⎦ Dɛr<br />

˜ = (1/ɛr(y1), 1/ɛr(y2), . . . , 1/ɛr(yN)).<br />

<br />

k Im(ɛr(x, y)) ≥ 0 <br />

Im(GE) <br />

<br />

<br />

<br />

<br />

<br />

<br />

u ∈ H 1 M(Ω) := {u ∈ H 1 (Ω) ∩ H 1/2<br />

00 (Γ), u = 0 ∂Ω\Γ}<br />

a(u, v) = −(gM, v)Γ,<br />

<br />

<br />

a(u, v) = − ∇u · ∇vdxdy +<br />

Ω<br />

<br />

(gM, v)Γ =<br />

Γ<br />

Ω<br />

k 2 <br />

u¯vdxdy + IM(u)¯v(x, 0)dx,<br />

Γ<br />

gM(x)¯v(x, 0)dx,<br />

H 1/2<br />

00 (Γ) = {u ∈ H1/2 (Γ) : ũ ∈ H 1/2 (R) ũ = 0 R\Γ u = ũ}.<br />

{xi, yj} <br />

Th Ω <br />

⎤<br />

⎥ ,<br />

⎥<br />


K ⊂ Ω Ks Γ V M h ∈ H1 M (Ω)<br />

<br />

vh ∈ V M h <br />

V M h = {vh ∈ H 1 M(Ω) : vh|K ∈ (P1 × P1)(K) K ∈ Th}.<br />

vh(x, y) =<br />

ξi(x) <br />

<br />

<br />

AM BM<br />

<br />

<br />

B T M<br />

TM<br />

M<br />

i=1<br />

N+1 <br />

j=1<br />

u<br />

ub<br />

vijξi(x)ξj(y),<br />

<br />

0<br />

=<br />

a M <br />

′<br />

mn = − ξ i1<br />

Ω<br />

(x)ξj1 (y)ξ′ i2 (x)ξj2 (y) + ξi1 (x)ξ′ j1 (y)ξi2 (x)ξ′ j2 (y) dxdy<br />

<br />

+ k<br />

Ω<br />

2 ξi1 (x)ξj1 (y)ξi2 (x)ξj2 (y)dxdy, i1, i2 = 1, 2, . . . , M; j1, j2 = 1, 2, . . . , N,<br />

b M <br />

′<br />

m,i2 = − ξ i1<br />

Ω<br />

(x)ξj1 (y)ξ′ i2 (x)ξN+1(y) + ξi1 (x)ξ′ j1 (y)ξi2 (x)ξ′ N+1(y) dxdy<br />

<br />

+ k<br />

Ω<br />

2 ξi1 (x)ξj1 (y)ξi2 (x)ξN+1(y)dxdy, i1, i2 = 1, 2, . . . , M; j1 = 1, 2, . . . , N,<br />

t M <br />

′<br />

i1,i2 = − ξ i1<br />

Ω<br />

(x)ξN+1(y)ξ ′ i2 (x)ξN+1(y) + ξi1 (x)ξ′ N+1(y)ξi2 (x)ξ′ N+1(y) dxdy<br />

<br />

+ k<br />

Ω<br />

2 ξi1 (x)ξN+1(y)ξi2 (x)ξN+1(y)dxdy<br />

<br />

+ IM(ξi2<br />

Γ<br />

)ξi1 (x)dx, i1, i2 = 1, 2, . . . , M,<br />

f M <br />

i1 = − gMξi1<br />

Γ<br />

(x)dx, i1 = 1, 2, . . . , M,<br />

m = (i1 − 1)N + j1, n = (i2 − 1)N + j2.<br />

<br />

<br />

A1 = hxA D x A2 = hyA D y <br />

C1 = hx<br />

⎡<br />

⎢<br />

⎣<br />

fM<br />

<br />

,<br />

AM = A1 ⊗ C2 + C1 ⊗ A2 + C1 ⊗ C2M,<br />

BM = hy<br />

6 A1 ⊗ eN + 1<br />

C1 ⊗ eN + cN+1C1 ⊗ eN,<br />

2/3 1/6<br />

1/6 2/3 1/6<br />

<br />

1/6 2/3<br />

⎤<br />

hy<br />

⎡<br />

⎥<br />

⎦ , C2<br />

⎢<br />

= hy ⎢<br />

⎣<br />

2/3 1/6<br />

1/6 2/3 1/6<br />

<br />

1/6 2/3<br />

⎤<br />

⎥<br />

⎦ ,


C2M <br />

0<br />

(C2M)ij =<br />

−b<br />

k 2 (y)ξi(y)ξj(y)dy, cN+1 =<br />

0<br />

−b<br />

k 2 (y)ξN(y)ξN+1(y)dy.<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

ψ = ∂u <br />

<br />

∂y<br />

ψ = ɛ −1<br />

r<br />

H 1 e (Ω) = {u ∈ H 1 (Ω), ∂u<br />

∂n<br />

y=0 +<br />

<br />

∂u <br />

<br />

∂y<br />

.<br />

y=0 −<br />

∈ H−1/2<br />

00<br />

.<br />

(Γ), u = IE( ∂u<br />

) Γ},<br />

∂n<br />

Heb(Γ) = {φ ∈ H −1/2 (Γ) : v ∈ H 1 e (Ω) ∂v<br />

∂y<br />

= φ Γ}.<br />

u ∈ H 1 e (Ω) ψ ∈ Heb(Γ) <br />

−(ɛ −1<br />

r ∇u, ∇v) + (k 2 0µru, v) + (ψ, v)Γ = 0, v ∈ H 1 e (Ω),<br />

(u, φ)Γ − (IE(ψ), φ)Γ = (gE, φ)Γ, φ ∈ Heb(Γ).<br />

<br />

u ψ <br />

V E h ∈ H1 e (Ω) W E h ∈ Heb(Γ) <br />

<br />

vh ∈ V E h φh ∈ W E h <br />

V E h = {vh ∈ H 1 e (Ω) : vh|K ∈ (P1 × P1)(K) K ∈ Th},<br />

W E h = {φh ∈ Heb(Γ) : φh|Ks ∈ P1(Ks) Ks ∈ Γ}.<br />

vh(x, y) =<br />

φh(x) =<br />

M+1 <br />

i=0<br />

M+1 <br />

i=0<br />

N+1 <br />

j=0<br />

vijξi(x)ξj(y), (x, y) ∈ Ω,<br />

φiξi(x), x ∈ Γ,<br />

ξi(x) Γ <br />

<br />

vh(x, 0) =<br />

M+1 <br />

vi,N+1ξi(x).<br />

i=0


a E <br />

mn = −<br />

<br />

+<br />

Ω <br />

b E m,i2 =<br />

Ω<br />

AE BE<br />

B T E TE<br />

u<br />

ψ<br />

<br />

0<br />

=<br />

ɛ −1 ′<br />

r ξ i1 (x)ξj1 (y)ξ′ i2 (x)ξj2 (y) + ξi1 (x)ξ′ j1 (y)ξi2 (x)ξ′ j2 (y) dxdy<br />

fE<br />

<br />

, <br />

k 2 0µrξi1 (x)ξj1 (y)ξi2 (x)ξj2 (y)dxdy, i1, i2 = 0, 1, . . . , M + 1; j1, j2 = 0, 1, . . . , N + 1,<br />

<br />

ξi1<br />

Γ<br />

(x)ξi2 (x)dx, i1, i2 = 0, 1, . . . , M + 1,<br />

t E i1,i2 = IE(ξi2<br />

Γ<br />

(x′ ))ξi1 (x)dx, i1, i2 = 0, 1, . . . , M + 1,<br />

f E i1 =<br />

<br />

gE(x)ξi1<br />

Γ<br />

(x)dx, i1 = 0, 1, . . . , M + 1,<br />

m = i1(N + 2) + j1, n = i2(N + 2) + j2.<br />

ɛr = ɛr(y) <br />

A N 1 = hxA N x <br />

C N 1 = hx<br />

⎡<br />

⎢<br />

⎣<br />

AE = A N 1 ⊗ ˜ C2E + C N 1 ⊗ A ND<br />

2E + k 2 0µrC N 1 ⊗ C N 2 ,<br />

BE = C1 ⊗ eN+2,<br />

1/3 1/6<br />

1/6 2/3 1/6<br />

<br />

1/6 2/3 1/6<br />

1/6 1/3<br />

A ND<br />

2E ˜ C2E <br />

(A ND<br />

0<br />

2E )ij = −<br />

−b<br />

⎤<br />

⎥<br />

⎦<br />

, C N 2 = hy<br />

⎡<br />

⎢<br />

⎣<br />

ɛ −1<br />

r (y)ξ ′ i(y)ξ ′ j(y)dy, ( ˜ C2E)ij =<br />

1/3 1/6<br />

1/6 2/3 1/6<br />

<br />

1/6 2/3 1/6<br />

1/6 1/3<br />

0<br />

−b<br />

ɛ −1<br />

r (y)ξi(y)ξj(y)dy.<br />

<br />

<br />

GM<br />

GE TM TE <br />

Jν(z) Yν(z) H (1)<br />

1<br />

H (1)<br />

1 (z) = J1(z) + iY1(z).<br />

(z) <br />

⎤<br />

⎥ ,<br />

⎥<br />


J1(z) ∼ O(z), Y1(z) ∼ O( 1<br />

),<br />

z<br />

z → 0,<br />

IM(u) <br />

J1(z) = J1(z)/z <br />

<br />

<br />

(IM(u)(xi, 0)) = k0<br />

2<br />

a<br />

0<br />

1<br />

|xi − x ′ | J1(k0|xi − x ′ |)u(x ′ , 0)dx ′ ≈ (g M ij )u(xj, 0),<br />

(g M ij ) = k2 0 hx<br />

2 J1(k0|xi − xj|),<br />

<br />

<br />

e.g. <br />

<br />

a<br />

(IM(u)) = −1<br />

=<br />

2 0<br />

Y1(k0|x − x ′ |)u(x ′ , 0)<br />

(x − x ′ ) 2 dx ′ ≈ (g M ij )u(xj, 0),<br />

Y1(z) = zY1(z) (gM ij ) = −αij Y1(k0|xi − xj|)/2 <br />

αij =<br />

⎧<br />

⎪⎨<br />

⎪⎩<br />

1 (1 − ln 2), |i − j| = 1,<br />

hx<br />

− 2 , i = j,<br />

hx<br />

1 (j−i)2<br />

h ln x (j−i) 2 , .<br />

−1<br />

O(hx)<br />

<br />

<br />

<br />

<br />

IE(v)(x) = I (1)<br />

E (v)(x) + I(2)<br />

E (v)(x),<br />

I (1)<br />

<br />

1<br />

E (v)(x) =<br />

2 Γ<br />

I (2)<br />

<br />

i<br />

E (v)(x) = −<br />

2 Γ<br />

J0(z) I (1)<br />

E<br />

I (1)<br />

E<br />

I (1)<br />

E (v)(xi) = 1<br />

2<br />

(v)(x) <br />

<br />

Γ<br />

1<br />

ɛr(x ′ ) Y0(k0|x − x ′ |)v(x ′ )dx ′ ,<br />

1<br />

ɛr(x ′ ) J0(k0|x − x ′ |)v(x ′ )dx ′ . <br />

Y0(z) ∼ ( 2 z<br />

ln<br />

π 2 )J0(z), z → 0,<br />

1<br />

ɛr(x ′ ) Y0(k0|xi − x ′ |)v(x ′ )dx ′ + 1<br />

2<br />

(v)(x) I(2)<br />

E (v)(x) <br />

<br />

Γ<br />

1<br />

ɛr(x ′ )<br />

2<br />

π ln k0|xi − x ′ |<br />

2<br />

<br />

J0(0)v(x ′ )dx ′ ,


Y0(z) = Y0(z) − ( 2<br />

π<br />

<br />

1<br />

2<br />

<br />

Γ<br />

ln z<br />

2 )J0(0) <br />

1<br />

ɛr(x ′ ) Y0(k0|xi − x ′ |)v(x ′ )dx ′ ≈ <br />

i.e.<br />

<br />

1<br />

2 Γ<br />

1<br />

ɛr(x ′ )<br />

<br />

2<br />

π ln k0|xi − x ′ |<br />

2<br />

<br />

<br />

<br />

<br />

J0(0)v(x ′ )dx ′ ≈ J0(0) <br />

π<br />

j<br />

I (1)<br />

E (v)(xi) ≈ <br />

j<br />

j<br />

hx<br />

2 Y0(k0|xi − xj|) v(xj)<br />

ɛr(xj) .<br />

<br />

v(xj)<br />

ɛr(xj) Γ<br />

(g E ij) v(xj)<br />

ɛr(xj) ,<br />

(g E ij) = hx<br />

2 Y0(k0|xi − xj|) + J0(0)<br />

xj+1<br />

π xj−1<br />

ln k0|(xi − x ′ )|<br />

ξj(x<br />

2<br />

′ )dx ′<br />

<br />

,<br />

ln k0|xi − x ′ |<br />

ξj(x<br />

2<br />

′ )dx ′ .<br />

I (2)<br />

E (v)(x) <br />

I (2)<br />

E (v)(xi) = − 1<br />

<br />

2 Γ<br />

1<br />

ɛr(x ′ ) J0(k0|xi − x ′ |)v(x ′ )dx ′ ≈ <br />

j<br />

(g E ij) v(xj)<br />

ɛr(xj)<br />

(g E ij) = − hx<br />

2 J0(k0|xi − xj|).<br />

<br />

<br />

(g M ij )<br />

(g E ij )<br />

<br />

(gM ij )<br />

<br />

GM = Gre M + iGim M GE = Gre E + iGim E Gre M = Gim M =<br />

<br />

(gM ij )<br />

<br />

Gre E =<br />

<br />

(gE ij )<br />

<br />

Gim E =<br />

<br />

(gE ij )<br />

<br />

k Im(ɛr(x, y)) ≥ 0<br />

GE Gim M Gim E <br />

<br />

G im M <br />

G im M G im E <br />

TM TE <br />

<br />

H (1)<br />

1 (z)<br />

z<br />

= H (1) d<br />

0 (z) −<br />

dz H(1) 1<br />

(z) = H(1)<br />

0<br />

d2<br />

(z) + H(1)<br />

dz2 0 (z),


t M ij = ik0<br />

2<br />

= ik2 0<br />

2<br />

− i<br />

2<br />

<br />

<br />

H (1)<br />

1 (k0|x − x ′ |)<br />

|x − x ′ |<br />

Γ Γ<br />

xi+1 xj+1<br />

xi−1 xj−1<br />

xi+1 xj+1<br />

xi−1<br />

xj−1<br />

ξi(x)ξj(x ′ )dxdx ′<br />

H (1)<br />

0 (k0(x − x ′ ))ξi(x)ξj(x ′ )dxdx ′<br />

H (1)<br />

0 (k0(x − x ′ ))ξ ′ i(x)ξ ′ j(x ′ )dxdx ′ .<br />

H (1)<br />

0 (z) <br />

<br />

t E ij = − i<br />

xi+1 xj+1<br />

H<br />

2 xi−1 xj−1<br />

(1)<br />

0 (k0|x − x ′ |)ξi(x)ξj(x ′ )dxdx ′ ,<br />

<br />

<br />

<br />

<br />

<br />

<br />

δ = hx/5<br />

1 <br />

0.25 a = 1.0 b = 0.25 <br />

ɛr = 1.0 ɛr = 4 + i <br />

<br />

⎧<br />

⎨ ɛr0 , −b/3 ≤ y < 0,<br />

ɛr(x, y) = 1.5ɛr0 , −2b/3 ≤ y < −b/3,<br />

⎩<br />

2ɛr0 , −b ≤ y < −2b/3.<br />

<br />

k0 = 2π <br />

<br />

σ = 4<br />

|P (φ)| 2 ,<br />

φ P <br />

P (φ) = k0<br />

2<br />

k0<br />

<br />

sin φ<br />

Γ<br />

u(x, 0)e ik0x cos φ dx.<br />

<br />

k0 = 2π <br />

θ = 0


PHASE<br />

RCS σ/λ (dB)<br />

MAGNITUDE<br />

3<br />

2<br />

1<br />

−100<br />

(a)<br />

0<br />

0 0.2 0.4 0.6 0.8 1<br />

x<br />

(b)<br />

50<br />

0<br />

−50<br />

0 0.2 0.4 0.6 0.8 1<br />

x<br />

(c)<br />

20<br />

0<br />

−20<br />

−40<br />

−60<br />

−80<br />

100 120 140<br />

φ (degree)<br />

160 180<br />

PHASE<br />

RCS σ/λ (dB)<br />

MAGNITUDE<br />

3<br />

2<br />

1<br />

−100<br />

<br />

(d)<br />

0<br />

0 0.2 0.4 0.6 0.8 1<br />

x<br />

(e)<br />

50<br />

0<br />

−50<br />

0 0.2 0.4 0.6 0.8 1<br />

x<br />

(f)<br />

20<br />

0<br />

−20<br />

−40<br />

−60<br />

−80<br />

100 120 140<br />

φ (degree)<br />

160 180<br />

<br />

k0 = 2π ɛr = 1.0<br />

ɛr = 4 + i <br />

<br />

k0 = 16π ɛr = 4+i <br />

Γ M = N = 1024<br />

θ = 0<br />

<br />

k0 <br />

<br />

N = M = 2048 M <br />

x MN <br />

<br />

<br />

u:,N+1 O(M 2 ) M × M


MAGNITUDE<br />

2<br />

1.5<br />

1<br />

0.5<br />

(a): k 0 =16π,ε r =4+i,θ=0<br />

0<br />

0 0.2 0.4 0.6 0.8 1<br />

x<br />

2<br />

1.5<br />

1<br />

0.5<br />

<br />

(b): k 0 =16π,inhomogeneous medium,θ=0<br />

0<br />

0 0.2 0.4 0.6 0.8 1<br />

k0 = 16π <br />

ɛr ɛr = 4 + i <br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

MAGNITUDE<br />

x


δ = hx/5<br />

k0 <br />

M × N <br />

k0 = 4π 256 2 <br />

512 2 <br />

1024 2 <br />

2048 2 <br />

k0 = 8π 256 2 <br />

512 2 <br />

1024 2 <br />

2048 2 <br />

k0 = 16π 256 2 <br />

512 2 <br />

1024 2 <br />

2048 2 <br />

k0 = 32π 256 2 <br />

512 2 <br />

1024 2 <br />

2048 2 <br />

k0 = 4π 256 2 <br />

ɛr = 4 + 512 2 <br />

1024 2 <br />

2048 2 <br />

k0 = 8π 256 2 <br />

512 2 <br />

1024 2 <br />

2048 2


δ = hx/5<br />

k0 <br />

M × N <br />

k0 = 4π 256 2 <br />

512 2 <br />

1024 2 <br />

2048 2 <br />

k0 = 8π 256 2 <br />

512 2 <br />

1024 2 <br />

2048 2 <br />

k0 = 16π 256 2 <br />

512 2 <br />

1024 2 <br />

2048 2 <br />

k0 = 32π 256 2 <br />

512 2 <br />

1024 2 <br />

2048 2 <br />

k0 = 4π 256 2 <br />

ɛr = 4 + 512 2 <br />

1024 2 <br />

2048 2 <br />

k0 = 8π 256 2 <br />

512 2 <br />

1024 2 <br />

2048 2


δ = hx/5<br />

k0 <br />

M × N <br />

k0 = 4π 256 2 <br />

512 2 <br />

1024 2 <br />

2048 2 <br />

k0 = 8π 256 2 <br />

512 2 <br />

1024 2 <br />

2048 2 <br />

k0 = 16π 256 2 <br />

512 2 <br />

1024 2 <br />

2048 2 <br />

k0 = 32π 256 2 <br />

512 2 <br />

1024 2 <br />

2048 2 <br />

k0 = 4π 256 2 <br />

ɛr = 4 + 512 2 <br />

1024 2 <br />

2048 2 <br />

k0 = 8π 256 2 <br />

512 2 <br />

1024 2 <br />

2048 2

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!