EXHIBIT 3(i)
 
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                       RESTATED ARTICLES OF INCORPORATION
 
                                       OF
 
                                  PLEXUS CORP.,
 
                             as amended and adopted
                                  March 7, 2001
 
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                                    ARTICLE I
                                      NAME
 
         The name of the corporation is PLEXUS CORP.
 
 
                                   ARTICLE II
                                    PURPOSES
 
         The purposes for which the corporation is organized are to engage in
any lawful activity within the purposes for which corporations may be organized
under the Wisconsin Business Corporation Law.
 
 
                                   ARTICLE III
                                  CAPITAL STOCK
 
A.       AUTHORIZED STOCK
 
         The authorized capital stock of the Corporation shall consist of One
Hundred Eighty-Five Million Shares (205,000,000), itemized by classes as follow:
 
                  1. One Hundred Eighty Million (200,000,000) Shares of Common
Stock, one cent ($.01) par value (the "Common Stock").
 
                  2. Five Million (5,000,000) Shares of Preferred Stock, one
cent ($.01) par value (the "Preferred Stock").
 
 
B.       [unused]
 
 
<PAGE>   2
 
 
 
C.       PREFERRED STOCK
 
         The Preferred Stock may be issued in series, and authority is vested in
the Board of Directors, from time to time, to establish and designate series and
to fix the variations in the powers, preferences, rights, qualifications,
limitations or restrictions of any series of the Preferred Stock, but only with
respect to:
 
                  1.       the rate of dividend;
 
                  2.       the price and terms and conditions on which shares
                           may be redeemed;
 
                  3.       the amount payable upon shares in the event of
                           voluntary or involuntary liquidation;
 
                  4.       sinking fund provisions for the redemption or
                           purchase of shares;
 
                  5.       the terms and conditions on which shares may be
                           converted into shares of any other class or series of
                           the same or any other class of stock of the
                           corporation, if the shares of any series are issued
                           with the privilege of conversion; and
 
                  6.       voting rights, if any.
 
         Except as to the matters expressly set forth above, all series of the
Preferred Stock shall have the same preferences, limitations and relative rights
and shall rank equally, share ratably and be identical in all respects as to all
matters. All shares of any one series of the Preferred Stock shall be alike in
every particular.
 
                                   ARTICLE IV
                                REGISTERED OFFICE
 
         The corporation's registered office and registered agent at such office
are:
 
                  Registered Office:          55 Jewelers Park Drive
                                              P.O. Box 156
                                              Neenah WI 54956
 
                  Registered Agent:           Joseph D. Kaufman
 
 
 
 
                                        2
 
<PAGE>   3
 
 
 
                                    ARTICLE V
                                    DIRECTORS
 
         The number of directors, which shall be not less than three (3), shall
be fixed by, or in the manner provided in, the By-laws.
 
 
                                   ARTICLE VI
                           DENIAL OF PREEMPTIVE RIGHTS
 
         The shareholders of the corporation are denied all preemptive rights.
 
 
                                   ARTICLE VII
                          RIGHT TO PURCHASE OWN SHARES
 
         The corporation shall have the right to acquire its own shares from
time to time, upon such terms and conditions as the Board of Directors shall
fix.
 
 
                                    * * * * *
 
 
 
                                        3
 
<PAGE>   4
 
 
 
 
                             Exhibit A to Article 3
 
 
                                      FORM
                                       OF
         CERTIFICATE OF DESIGNATION, PREFERENCES, RIGHTS AND LIMITATIONS
                                       OF
                  SERIES A JUNIOR PARTICIPATING PREFERRED STOCK
                                       OF
                                  PLEXUS CORP.
 
 
 
(Pursuant to Section 180.0602 of the Wisconsin Business Corporation Law)
 
 
         Plexus Corp., a corporation organized and existing under the Wisconsin
Business Corporation Law (the "Corporation"), does hereby certify that, pursuant
to authority conferred upon its Board of Directors by its Restated Articles of
Incorporation and by the provisions of 180.0602 of the Wisconsin Business
Corporation Law, the following resolution was adopted by its Board of Directors
at a meeting duly held on August 13, 1998:
 
         RESOLVED, that pursuant to the authority conferred upon the Board of
Directors of the Corporation (the "Board") by the provisions of the Restated
Articles of Incorporation of the Corporation and the provisions of Section
180.0602 of the Wisconsin Business Corporation Law, there is hereby created a
series of Preferred Stock of the Corporation, which series shall have the
following powers, designations, preferences and relative, participating,
optional and other special rights, and the qualifications, limitations or
restrictions thereof, in addition to those set forth in the Restated Articles of
Incorporation of the Corporation:
 
         Section 1. Designation of Series A Junior Participating Preferred
Stock: Number of Shares.
 
         There is designated a series of Preferred Stock titled as "Series A
Junior Participating Preferred Stock," $.01 par value per share (the "Series A
Preferred Stock"), and the authorized number of shares constituting the Series A
Preferred Stock shall be 1,000,000. Such number of authorized shares may be
increased or decreased, from time to time, by resolution of the Board; provided,
however, that no such decrease shall reduce the number of authorized shares of
the Series A Preferred Stock to a number less than the number of shares of the
Series A Preferred Stock then outstanding, plus the number of such shares then
reserved for issuance upon the exercise of any outstanding options, warrants or
rights or the exercise of any conversion or exchange privilege contained in any
outstanding security issued by the Corporation.
 
 
                                       A-4
 
<PAGE>   5
 
 
 
         Section 2. Dividends and Distributions.
 
         (A) Subject to the rights of the holders of shares of any other series
of Preferred Stock (or shares of any other class of capital stock of the
Corporation) ranking senior to the Series A Preferred Stock with respect to
dividends, the holders of shares of the Series A Preferred Stock, in preference
to the holders of shares of Common Stock and of any other class of capital stock
of the Corporation ranking junior to the Series A Preferred Stock with respect
to dividends, shall be entitled to receive, when, as and if declared by the
Board out of funds legally available therefor, such dividends, subject to the
provision for adjustment hereinafter set forth, equal to 100 times the aggregate
per share amount of all cash dividends, and 100 times the aggregate per share
amount (payable in kind) of all non-cash dividends or other distributions other
than a dividend payable in shares of Common Stock or subdivision of the
outstanding shares of Common Stock (by reclassification or otherwise), declared
on the Common Stock. In the event the Company shall at any time after August 13,
1998 (i) declare any dividend on Common Stock payable in shares of Common Stock,
(ii) subdivide the outstanding Common Stock, or (iii) combine the outstanding
Common Stock into a smaller number of shares, then in each such case the amount
to which holders of shares of Series A Preferred Stock were entitled immediately
prior to such event shall be adjusted by multiplying such amount by a fraction
the numerator of which is the number of shares of Common Stock outstanding
immediately after such event and the denominator of which is the number of
shares of Common Stock that were outstanding immediately prior to such event.
 
         (B) The Board shall declare, out of funds legally available therefor, a
dividend or distribution on the Series A Preferred Stock, as provided in
paragraph (A) of this Section 2, immediately after it has declared a dividend or
distribution on the Common Stock (other than a dividend payable in shares of
Common Stock).
 
         Section 3. Voting Rights. In addition to any other voting rights
required by applicable law, the holders of shares of the Series A Preferred
Stock shall have the following voting rights:
 
         (A) Each share of the Series A Preferred Stock shall entitle the holder
thereof to 100 votes on all matters submitted to a vote of the shareholders of
the Corporation. The multiple of 100 (the "Voting Multiple") set forth in the
preceding sentence shall be adjusted from time to time as hereinafter provided
in this paragraph (A). In the event that the Corporation shall at any time after
the effective date of this Resolution of the Board ("Resolution") (i) declare or
pay any dividend on Common Stock payable in shares of Common Stock, or (ii)
effect a subdivision, combination or consolidation of the outstanding shares of
Common Stock (by reclassification or otherwise than by payment of a dividend in
shares of Common Stock) into a greater or lesser number of shares of Common
Stock, then, in each such case, the Voting Multiple thereafter applicable to the
determination of the number of votes per share to which the holders of shares of
the Series A Preferred Stock shall be entitled shall be the Voting Multiple in
effect immediately prior to such event multiplied by a fraction, the numerator
of which shall be the number of shares of Common Stock outstanding immediately
after such event and the denominator of which shall be the number of shares of
Common Stock that were outstanding immediately prior to such
 
                                       A-5
 
<PAGE>   6
 
event.
 
         (B) Except as otherwise provided in this Resolution, in any other
resolution establishing another series of Preferred Stock (or any series of any
other class of capital stock of the Corporation) or by applicable law, the
holders of the Series A Preferred Stock, the holders of Common Stock and the
holders of any other class of capital stock of the Corporation having general
voting rights shall vote together as a single class on all matters submitted to
a vote of the shareholders of the Corporation.
 
         (C) Except as otherwise provided in this Resolution or by applicable
law, the holders of the Series A Preferred Stock shall have no special voting
rights and their consent shall not be required (except to the extent provided in
paragraph (B) of this Section 3 for the taking of any corporate action).
 
         Section 4. Certain Restrictions.
 
         (A) Whenever dividends or other distributions payable on the Series A
Preferred Stock as provided in Section 2 are in arrears, thereafter and until
all accrued and unpaid dividends and distributions, whether or not declared, on
outstanding shares of the Series A Preferred Stock shall have been paid in full,
the Corporation shall not:
 
                  (i) Declare or pay dividends or make any other distributions
on any shares of any class of capital stock of the Corporation ranking junior
(either as to dividends or upon liquidation, dissolution or winding up of the
Corporation) to the Series A Preferred Stock;
 
                  (ii) Declare or pay dividends, or make any other
distributions, on any shares of any class of capital stock of the Corporation
ranking on a parity (either as to dividends or upon liquidation, dissolution or
winding up of the Corporation) with the Series A Preferred Stock, except
dividends paid ratably on the Series A Preferred Stock and all such parity stock
on which dividends are accrued and unpaid in proportion to the total amounts to
which the holders of all such shares are then entitled;
 
                  (iii) Redeem, purchase or otherwise acquire for consideration
any shares of any class of capital stock of the Corporation ranking junior
(either as to dividends or upon liquidation, dissolution or winding up of the
Corporation) to the Series A Preferred Stock, except that the Corporation may at
any time redeem, purchase or otherwise acquire any shares of such junior stock
in exchange for other shares of any class of capital stock of the Corporation
ranking junior (both as to dividends and upon dissolution, liquidation or
winding up of the Corporation) to the Series A Preferred Stock; or
 
 
 
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<PAGE>   7
 
 
 
                  (iv) Purchase or otherwise acquire for consideration any
shares of the Series A Preferred Stock or any shares of any class of capital
stock of the Corporation ranking on a parity (either as to dividends or upon
liquidation, dissolution or winding up of the Corporation) with the Series A
Preferred Stock, or redeem any shares of such parity stock, except in accordance
with a purchase offer made in writing or by publication to the holders of all
such shares upon such terms and conditions as the Board, after taking into
consideration the respective annual dividend rates and the other relative
powers, preferences and rights of the respective series and classes of such
shares, shall determine in good faith will result in fair and equitable
treatment among the respective holders of shares of all such series and classes.
 
         (B) The Corporation shall not permit any subsidiary of the Corporation
to purchase or otherwise acquire for consideration any shares of any class of
capital stock of the Corporation unless the Corporation could, under paragraph
(A) of this Section 4, purchase or otherwise acquire such shares at such time
and in such manner.
 
         Section 5. Reacquired Shares. Any shares of the Series A Preferred
Stock purchased or otherwise acquired by the Corporation in any manner
whatsoever shall be retired and canceled promptly after such purchase or
acquisition. All such canceled shares shall thereupon become authorized and
unissued shares of Preferred Stock and may be reissued as part of any new series
of Preferred Stock, subject to the conditions and restrictions on issuance set
forth in the Restated Articles of Incorporation of the Corporation, from time to
time, in any other resolution establishing another series of Preferred Stock (or
any series of any other class of capital stock of the Corporation) or in any
applicable law.
 
         Section 6. Liquidation, Dissolution or Winding Up. Upon any liquidation
(whether voluntary or otherwise), dissolution or winding up of the Corporation,
no distribution shall be made (a) to the holders of shares of any class of
capital stock of the Corporation ranking junior (either as to dividends or upon
liquidation, dissolution or winding up of the Corporation) to the Series A
Preferred Stock unless, prior thereto, the holder of each outstanding share of
the Series A Preferred Stock shall have received an amount equal to the accrued
and unpaid dividends and distributions thereon, whether or not declared, to the
date of such payment, plus an amount equal to the greater of (i) $1.00, and (ii)
an aggregate amount, subject to adjustment as hereinafter provided in this
Section 6, equal to 100 times the aggregate per share amount to be distributed
to the holders of Common Stock, or (b) to the holders of shares of any class of
capital stock of the Corporation ranking on a parity (either as to dividends or
upon liquidation, dissolution or winding up of the Corporation) with the Series
A Preferred Stock, except distributions made ratably on the Series A Preferred
Stock and all such parity stock in proportion to the total amounts to which the
holders of all such shares are entitled upon such liquidation, dissolution or
winding up. In the event that the Corporation shall at any time after the
effective date of this Resolution (a) declare or pay any dividend on Common
Stock payable in shares of Common Stock, or (b) effect a subdivision,
combination or consolidation of the outstanding shares of Common Stock (by
reclassification or otherwise than by payment of a dividend in shares of Common
Stock) into a greater or lesser number of shares of Common Stock, then, in each
such case, the aggregate amount per share to which the holders of shares of the
Series A Preferred Stock would have been entitled to receive immediately prior
to such event pursuant to clause
 
 
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<PAGE>   8
 
 
 
(a)(ii) of the preceding sentence shall be adjusted by multiplying such
aggregate per share amount by a fraction, the numerator of which shall be the
number of shares of Common Stock outstanding immediately after such event and
the denominator of which shall be the number of shares of Common Stock that were
outstanding immediately prior to such event.
 
         Section 7. Consolidation, Merger, etc. In the event that the
Corporation shall be a party to any consolidation, merger, combination or other
transaction in which the outstanding shares of Common Stock are converted or
changed into or exchanged for other capital stock, securities, cash or other
property, or any combination thereof, then, in each such case, each share of the
Series A Preferred Stock shall at the same time be similarly converted or
changed into or exchange for an aggregate amount, subject to adjustment as
hereinafter provided in this Section 7, equal to 100 times the aggregate amount
of capital stock, securities, cash and/or other property (payable in kind), as
the case may be, into which or for which each share of Common Stock is being
converted or changed or exchanged. In the event that the Corporation shall at
any time after the effective date of this Resolution declare or pay any dividend
on Common Stock payable in shares of Common Stock or effect a subdivision,
combination or consolidation of the outstanding shares of Common Stock (by
reclassification or otherwise than by payment of a dividend in shares of Common
Stock) into a greater or lesser number of shares of Common Stock, then, in each
such case, the aggregate amount per share to which the holders of shares of the
Series A Preferred Stock would have been entitled to receive immediately prior
to such event pursuant to the preceding sentence shall be adjusted by
multiplying such aggregate per share amount by a fraction, the numerator of
which shall be the number of shares of Common Stock outstanding immediately
after such event and the denominator of which shall be the number of shares of
Common Stock that were outstanding immediately prior to such event.
 
         Section 8. No Redemption. The shares of the Series A Preferred Stock
shall not be redeemable at any time.
 
         Section 9. Rank. Unless otherwise provided in the resolution
establishing another series of Preferred Stock after the effective date of this
Resolution, the Series A Preferred Stock shall rank, as to the payment of
dividends and the making of any other distribution of assets of the Corporation,
senior to the Common Stock, but junior to all other series of the Preferred
Stock.
 
         Section 10. Amendments. The Restated Articles of Incorporation of the
Corporation shall not be amended in any manner which would materially alter or
change the powers, preferences and rights of the Series A Preferred Stock so as
to adversely affect any rights of the holders thereof without the affirmative
vote of the holders of at least two-thirds of the outstanding shares of the
Series A Preferred Stock, voting separately as a single class.
 
         Section 11. Fractional Shares. Fractional shares of the Series A
Preferred Stock may be issued, but, unless the Board shall otherwise determine,
only in multiples of one one-hundredth of a share. The holder of any fractional
share of the Series A Preferred Stock shall be entitled to receive dividends,
participate in distributions, exercise voting rights and have the benefit of all
other powers, preferences and rights relating to the Series A Preferred Stock in
the same proportion as such fractional share bears to a whole share.